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44 results on '"University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)"'

1. Large time behavior of the Vlasov-Navier-Stokes system on the torus

Author: Iván Moyano, Ayman Moussa, Daniel Han-Kwan, Centre de Mathématiques Laurent Schwartz (CMLS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire Jacques-Louis Lions (LJLL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and ANR-19-CE40-0004,SALVE,Singularités dans des limites asymptotiques d'équations de Vlasov(2019)
Subjects: Physics, Mechanical Engineering, Dirac (video compression format), 010102 general mathematics, Mathematical analysis, Complex system, Structure (category theory), Mathematics::Analysis of PDEs, Torus, Type (model theory), 01 natural sciences, Exponential function, 010101 applied mathematics, Mathematics (miscellaneous), Distribution function, Mathematics - Analysis of PDEs, FOS: Mathematics, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], 0101 mathematics, Analysis, Energy (signal processing), Analysis of PDEs (math.AP)
Abstract: International audience; We study the large time behavior of Fujita–Kato type solutions to the Vlasov–Navier–Stokes system set on $\T^3 \times \R^3$. Under the assumption that the initial so-called modulated energy is small enough, we prove that the distribution function converges to a Dirac mass in velocity, with exponential rate. The proof is based on the fine structure of the system and on a bootstrap analysis allowing us to get global bounds on moments.
Published: 2019

2. Lozenge tiling dynamics and convergence to the hydrodynamic equation

Author: Benoit Laslier, Fabio Lucio Toninelli, University of Cambridge [UK] (CAM), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Probabilités, statistique, physique mathématique (PSPM), Institut Camille Jordan [Villeurbanne] (ICJ), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), CNRS PICS grant 'Interfaces al ́eatoires discr`etes et dy-namiques de Glauber, and ANR-15-CE40-0020,LSD,Modèles stochastiques en grande dimension pour la physique statistique hors équilibre(2015)
Subjects: Physics, 010102 general mathematics, Probability (math.PR), Inverse, Statistical and Nonlinear Physics, Function (mathematics), 01 natural sciences, Parabolic partial differential equation, Projection (linear algebra), [MATH.MATH-PR]Mathematics [math]/Probability [math.PR], 010104 statistics & probability, Bernoulli's principle, FOS: Mathematics, Heat equation, Differentiable function, 0101 mathematics, Langevin dynamics, Mathematical Physics, ComputingMilieux_MISCELLANEOUS, Mathematics - Probability, Mathematical physics
Abstract: We study a reversible continuous-time Markov dynamics of a discrete $(2+1)$-dimensional interface. This can be alternatively viewed as a dynamics of lozenge tilings of the $L\times L$ torus, or as a conservative dynamics for a two-dimensional system of interlaced particles. The particle interlacement constraints imply that the equilibrium measures are far from being product Bernoulli: particle correlations decay like the inverse distance squared and interface height fluctuations behave on large scales like a massless Gaussian field. We consider a particular choice of the transition rates, originally proposed in [Luby-Randall-Sinclair]: in terms of interlaced particles, a particle jump of length $n$ that preserves the interlacement constraints has rate $1/(2n)$. This dynamics presents special features: the average mutual volume between two interface configurations decreases with time and a certain one-dimensional projection of the dynamics is described by the heat equation. In this work we prove a hydrodynamic limit: after a diffusive rescaling of time and space, the height function evolution tends as $L\to\infty$ to the solution of a non-linear parabolic PDE. The initial profile is assumed to be $C^2$ differentiable and to contain no "frozen region". The explicit form of the PDE was recently conjectured on the basis of local equilibrium considerations. In contrast with the hydrodynamic equation for the Langevin dynamics of the Ginzburg-Landau model [Funaki-Spohn,Nishikawa], here the mobility coefficient turns out to be a non-trivial function of the interface slope., Comment: 35 pages, 7 figures. v3: a few more typos corrected, remark 2.8 added. To appear on Comm. Math. Phys
Published: 2017
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3. Hydrodynamic limit equation for a lozenge tiling Glauber dynamics

Author: Benoît Laslier, Fabio Lucio Toninelli, University of Cambridge [UK] (CAM), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Institut Camille Jordan [Villeurbanne] (ICJ), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Probabilités, statistique, physique mathématique (PSPM), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL)
Subjects: Physics, Nuclear and High Energy Physics, Markov chain, Plane (geometry), Probability (math.PR), 010102 general mathematics, Mathematical analysis, FOS: Physical sciences, Statistical and Nonlinear Physics, Hamming distance, Mathematical Physics (math-ph), 01 natural sciences, Parabolic partial differential equation, Square (algebra), [MATH.MATH-PR]Mathematics [math]/Probability [math.PR], Nonlinear system, 0103 physical sciences, FOS: Mathematics, 010307 mathematical physics, Limit (mathematics), 0101 mathematics, Balanced flow, ComputingMilieux_MISCELLANEOUS, Mathematics - Probability, Mathematical Physics
Abstract: We study a reversible continuous-time Markov dynamics on lozenge tilings of the plane, introduced by Luby et al. Single updates consist in concatenations of $n$ elementary lozenge rotations at adjacent vertices. The dynamics can also be seen as a reversible stochastic interface evolution. When the update rate is chosen proportional to $1/n$, the dynamics is known to enjoy especially nice features: a certain Hamming distance between configurations contracts with time on average and the relaxation time of the Markov chain is diffusive, growing like the square of the diameter of the system. Here, we present another remarkable feature of this dynamics, namely we derive, in the diffusive time scale, a fully explicit hydrodynamic limit equation for the height function (in the form of a non-linear parabolic PDE). While this equation cannot be written as a gradient flow w.r.t. a surface energy functional, it has nice analytic properties, for instance it contracts the $\mathbb L^2$ distance between solutions. The mobility coefficient $\mu$ in the equation has non-trivial but explicit dependence on the interface slope and, interestingly, is directly related to the system's surface free energy. The derivation of the hydrodynamic limit is not fully rigorous, in that it relies on an unproven assumption of local equilibrium., Comment: 31 pages, 8 figures. v2: typos corrected, some proofs clarified. To appear on Annales Henri Poincare
Published: 2016

4. From the seminar on Mathematical Statistical Physics in Moscow State University, 1962–1994. Gibbs random fields on the lattice. Definitions, existence, uniqueness

Author: Yuri Suhov, Semen Bensionovich Shlosman, S. A. Pirogov, Robert Minlos, Eugene Pechersky, Inst. of the Information Transmission Problems (IITP RAS), Russian Academy of Sciences [Moscow] (RAS), CPT - E5 Physique statistique et systèmes complexes, Centre de Physique Théorique - UMR 7332 (CPT), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: Physics, Gibbs random fields, Lattice (order), [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], 010102 general mathematics, 0103 physical sciences, General Physics and Astronomy, 010307 mathematical physics, Uniqueness, Statistical physics, 0101 mathematics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012

5. From the seminar on Mathematical Statistical Physics in Moscow State University, 1962–1994. Contour technics

Author: E. Dinaburg, Semen Bensionovich Shlosman, S. A. Pirogov, Eugene Pechersky, Yuri Suhov, Inst. of the Information Transmission Problems (IITP RAS), Russian Academy of Sciences [Moscow] (RAS), CPT - E5 Physique statistique et systèmes complexes, Centre de Physique Théorique - UMR 7332 (CPT), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: Physics, 010104 statistics & probability, 010102 general mathematics, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], Calculus, General Physics and Astronomy, State (computer science), 0101 mathematics, 01 natural sciences, Engineering physics, History of science, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012

6. Prospects for GRB Science with the Fermi Large Area Telescope

Author: R. M. Kippen, Brenda Dingus, Sinéad McGlynn, Takashi Shimokawabe, Carmelo Sgrò, E. Moretti, Jonathan Granot, F. Kuehn, J. P. Norris, M. N. Mazziotta, P. D. Smith, R. E. Hughes, Nicola Omodei, M. Kuss, James Chiang, J. J. Russell, Felix Ryde, Jeffrey D. Scargle, P. Lubrano, N. Gehrels, E. Do Couto E Silva, P. Spinelli, Guido Barbiellini, Ryo Yamazaki, F. Longo, Brian L Winer, G. Bogaert, V. Pelassa, S. Cutini, V. Connaughton, F. Piron, Robert D. Preece, Matthew G. Baring, Takeshi Nakamori, Gerald J. Fishman, T. Kamae, N. Giglietto, Masanori Ohno, M. Razzano, P. M. Saz Parkinson, David L. Band, M. Olivo, Johann Cohen-Tanugi, F. de Palma, Magnus Axelsson, A. Galli, Gloria Spandre, Julie McEnery, Luca Baldini, Sylvain Guiriec, J. Bonnel, Elisabetta Bissaldi, M. Battelino, Denis Bastieri, Ronaldo Bellazzini, M. Stamatikos, N. Komin, Department of Zoology, University of Gothenburg (GU), CNR Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale delle Ricerche (CNR), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Joint Center for Astrophysics/Physics Department University of Maryland, University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Bureau d'Économie Théorique et Appliquée (BETA), Institut National de la Recherche Agronomique (INRA)-Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Hansen Experimental Physics Laboratory (HEPL), Stanford University [Stanford], Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Stanford Linear Accelerator Center (SLAC), Institut d'Informatique et de Mathématiques Appliquées de Grenoble (IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Department of Chemistry [Waterloo], University of Waterloo [Waterloo], Statistical Laboratory (DPMMS), University of Cambridge [UK] (CAM), Istituto Nazionale di Fisica Nucleare, Sezione di Trieste (INFN, Sezione di Trieste), National Institute for Nuclear Physics (INFN), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, NASA Goddard Space Flight Center (GSFC), Center for Research and Exploration in Space Science and Technology [GSFC] (CRESST), Stockholm Observatory Department of Astronomy, Stockholm University, Istituto Nazionale di Fisica Nucleare [Pisa] (INFN), Istituto Nazionale di Fisica Nucleare (INFN), Dipartimento di Fisica [Trieste], Università degli studi di Trieste = University of Trieste, Department of Physics and Astronomy [Houston], Rice University [Houston], Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Dipartimento di Fisica 'G. Galilei', Università degli Studi di Padova = University of Padua (Unipd), Department of Physics, Royal Institute of Technology (KTH), Max-Planck-Institut für Extraterrestrische Physik (MPE), Stanford University, SLAC National Accelerator Laboratory (SLAC), Hansen Experimental Physics Lab [Stanford] (HEPL), University of Alabama in Huntsville (UAH), Agenzia Spaziale Italiana (ASI), Istituto Nazionale di Fisica Nucleare, sezione di Bari (INFN, sezione di Bari), Dipartimento di Fisica 'M. Merlin' dell'Università e del Politecnico di Bari, Politecnico di Bari, Los Alamos National Laboratory (LANL), NASA Marshall Space Flight Center (MSFC), Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), University of Maryland System, Centre for Astrophysics Research [Hatfield], University of Hertfordshire [Hatfield] (UH), Department of Physics, Ohio State University, Laboratoire Aimé Cotton (LAC), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (INFN, Sezione di Perugia), Tokyo Institute of Technology [Tokyo] (TITECH), Department of Physics [Tokyo], Rikkyo University [Tokyo], Department of Physics and Astronomy [Denver], University of Denver, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Santa Cruz Institute for Particle Physics (SCIPP), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), NASA Ames Research Center (ARC), Center for Cosmology & AstroParticle Physics, Ohio State University [Columbus] (OSU), Department of Physics, The Ohio State University, Hiroshima Astrophysical Science Center, Hiroshima University, Department of Physical Sciences [Higashi-Hiroshima], The Fermi LAT Collaboration acknowledges support from a number of agencies and institutes for both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support from the Istituto Nazionale di Astrofisica in Italy for science analysis during the operations phase is also gratefully acknowledged., Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Statistical Laboratory [Cambridge], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Université de Lorraine (UL)-Université de Strasbourg (UNISTRA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), D. L., Band, M., Axelsson, L., Baldini, BARBIELLINI AMIDEI, Guido, M. G., Baring, D., Bastieri, M., Battelino, R., Bellazzini, Bissaldi, Elisabetta, G., Bogaert, J., Bonnell, J., Chiang, J., Cohen Tanugi, V., Connaughton, S., Cutini, F. d., Palma, B. L., Dingu, E. D. E., Silva, G., Fishman, A., Galli, N., Gehrel, N., Giglietto, J., Granot, S., Guiriec, R. E., Hughe, T., Kamae, N., Komin, F., Kuehn, M., Ku, Longo, Francesco, P., Lubrano, R. M., Kippen, M. N., Mazziotta, J. E., Mcenery, S., Mcglynn, Moretti, Elena, T., Nakamori, J. P., Norri, M., Ohno, M., Olivo, N., Omodei, V., Pelassa, F., Piron, R., Preece, M., Razzano, J. J., Russell, F., Ryde, P. M. S., Parkinson, J. D., Scargle, C., Sgro, T., Shimokawabe, P. D., Smith, G., Spandre, P., Spinelli, M., Stamatiko, B. L., Winer, and R., Yamazaki
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], gamma rays: bursts, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Fermi satellite, Astrophysics, 7. Clean energy, 01 natural sciences, High Energy Gamma-ray Astronomy, law.invention, Telescope, law, 0103 physical sciences, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Bursts, Spacecraft, business.industry, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Detector, Gamma rays, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Afterglow, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, Gamma-ray Bursts, business, Gamma-ray burst, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Fermi Gamma-ray Space Telescope
Abstract: The LAT instrument on the Fermi mission will reveal the rich spectral and temporal gamma-ray burst phenomena in the > 100 MeV band. The synergy with Fermi's GBM detectors will link these observations to those in the well explored 10-1000 keV range; the addition of the > 100 MeV band observations will resolve theoretical uncertainties about burst emission in both the prompt and afterglow phases. Trigger algorithms will be applied to the LAT data both onboard the spacecraft and on the ground. The sensitivity of these triggers will differ because of the available computing resources onboard and on the ground. Here we present the LAT's burst detection methodologies and the instrument's GRB capabilities., Accepted by ApJ
Published: 2009

7. Multiple coexisting states of liquid rope coiling

Author: Daniel Bonn, Herbert E. Huppert, Neil M. Ribe, Mehdi Habibi, Mark A. Hallworth, Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institute of Theoretical Geophysics [Cambridge] (ITG), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)-Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM), Institute for Advanced Studies in Basic Sciences, Institute for advanced Studies in Basic Sciences, Laboratoire de Physique Statistique de l'ENS (LPS), Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut des Neurosciences Cellulaires et Intégratives (INCI), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), University of Amsterdam Van der Waals-Zeeman Institute (VAN DER WAALS-ZEEMAN INSTITUTE), University of Amsterdam [Amsterdam] (UvA), Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institute for Advanced Studies in Basic Sciences (IASBS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Soft Matter (WZI, IoP, FNWI)
Subjects: Physics, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], Mechanical Engineering, Bending, Viscous liquid, Condensed Matter Physics, Rotation, 01 natural sciences, Instability, String (physics), 010305 fluids & plasmas, Gravitation, Classical mechanics, Mechanics of Materials, 0103 physical sciences, Life Science, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Atomic physics, 010306 general physics, Falling (sensation), ComputingMilieux_MISCELLANEOUS, Rope
Abstract: A thin ‘rope’ of viscous fluid falling from a sufficient height onto a surface forms a series of regular coils. Here we investigate theoretically and experimentally a curious feature of this instability: the existence of multiple states with different frequencies at a fixed value of the fall height. Using a numerical model based on asymptotic ‘thin rope’ theory, we determine curves of coiling frequency Ω vs. fall height H as functions of the fluid viscosity ν, the diameter d of the injection hole, the volumetric injection rate Q, and the acceleration due to gravity g. In addition to the three coiling modes previously identified (viscous, gravitational and inertial), we find a new multivalued ‘inertio-gravitational’ mode that occurs at heights intermediate between gravitational and inertial coiling. In the limit when the rope is strongly stretched by gravity and Π1 ≡ (ν 5 /gQ 3 ) 1/5 � 1, inertio-gravititational coiling occurs in the height range O(Π −1/6 1 ) H (g/ν 2 ) 1/3 O(Π −5/48 1 ). The frequencies of the individual branches are proportional to (g/H) 1/2 , and agree closely with the eigenfrequencies of a whirling liquid string with negligible resistance to bending and twisting. The number of coexisting branches scales as Π 5/32 1 . The predictions of the numerical model are in excellent agreement with laboratory experiments performed by two independent groups using different apparatus and working fluids. The experiments further show that interbranch transitions in the inertio-gravitational regime occur via an intermediate state with a ‘figure of eight’ geometry that changes the sense of rotation of the coiling.
Published: 2006

8. Exact fluctuating hydrodynamics of active lattice gases—typical fluctuations

Author: Tal Agranov, Sunghan Ro, Vivien Lecomte, Yariv Kafri, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Physics Department, Technion-Israel Institute of Technology, Haifa 32000, Israel, Technion - Israel Institute of Technology [Haifa], Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: Statistics and Probability, Collective behavior, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], Lattice (group), FOS: Physical sciences, Condensed Matter - Soft Condensed Matter, 01 natural sciences, 010305 fluids & plasmas, Critical point (thermodynamics), Phase (matter), 0103 physical sciences, Statistical physics, [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech], 010306 general physics, Condensed Matter - Statistical Mechanics, ComputingMilieux_MISCELLANEOUS, Physics, Statistical Mechanics (cond-mat.stat-mech), Statistical and Nonlinear Physics, Renormalization group, 3. Good health, Active matter, Thermodynamic limit, Soft Condensed Matter (cond-mat.soft), Ising model, Statistics, Probability and Uncertainty
Abstract: We extend recent results on the exact hydrodynamics of a system of diffusive active particles displaying a motility-induced phase separation to account for typical fluctuations of the dynamical fields. By calculating correlation functions exactly in the homogeneous phase, we find that two macroscopic length scales develop in the system. The first is related to the diffusive length of the particles and the other to the collective behavior of the particles. The latter diverges as the critical point is approached. Our results show that the critical behavior of the model in one dimension belongs to the universality class of a mean-field Ising model, both for static and dynamic properties, when the thermodynamic limit is taken in a specified manner. The results are compared to the critical behavior exhibited by the ABC model. In particular, we find that in contrast to the ABC model the density large deviation function, at its Gaussian approximation, does not contain algebraically decaying interactions but is of a finite, macroscopic, extent which is dictated by the diverging correlation length., Comment: 17 pages, 6 figures
Published: 2021

9. Non-additive large deviations function for the particle densities of driven systems in contact

Author: Eric Bertin, Jules Guioth, Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: [PHYS]Physics [physics], Statistics and Probability, Physics, Statistical and Nonlinear Physics, Mechanics, 01 natural sciences, 010305 fluids & plasmas, 0103 physical sciences, Particle, Statistics, Probability and Uncertainty, 010306 general physics, Deviation function, Stationary state, Condensed Matter - Statistical Mechanics
Abstract: We investigate the non-equilibrium large deviations function of the particle densities in two steady-state driven systems exchanging particles at a vanishing rate. We first derive through a systematic multi-scale analysis the coarse-grained master equation satisfied by the distribution of the numbers of particles in each system. Assuming that this distribution takes for large systems a large deviations form, we obtain the equation (similar to a Hamilton-Jacobi equation) satisfied by the large deviations function of the densities. Depending on the systems considered, this equation may satisfy or not the macroscopic detailed balance property, i.e., a time-reversibility property at large deviations level. In the absence of macroscopic detailed balance, the large deviations function can be determined as an expansion close to a solution satisfying macroscopic detailed balance. In this case, the large deviations function is generically non-additive, i.e., it cannot be split as two separate contributions from each system. In addition, the large deviations function can be interpreted as a non-equilibrium free energy, as it satisfies a generalization of the second law of thermodynamics, in the spirit of the Hatano-Sasa relation. Some of the results are illustrated on an exactly solvable driven lattice gas model., Comment: 31 pages, 1 figure
Published: 2019

10. Decay estimates for large velocities in the Boltzmann equation without cutoff

Author: Luis Silvestre, Cyril Imbert, Clément Mouhot, Département de Mathématiques et Applications - ENS Paris (DMA), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Department of Mathematics [Chicago], University of Chicago, École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Pointwise, Physics, General Mathematics, 010102 general mathematics, 01 natural sciences, Boltzmann equation, 010101 applied mathematics, Mathematics - Analysis of PDEs, FOS: Mathematics, Cutoff, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], 0101 mathematics, Mathematical physics, Analysis of PDEs (math.AP)
Abstract: We consider solutions $f=f(t,x,v)$ to the full (spatially inhomogeneous) Boltzmann equation with periodic spatial conditions $x \in \mathbb T^d$, for hard and moderately soft potentials \emph{without the angular cutoff assumption}, and under the \emph{a priori} assumption that the main hydrodynamic fields, namely the local mass $\int\_v f(t,x,v)$ and local energy $\int\_v f(t,x,v)|v|^2$ and local entropy $\int\_v f(t,x,v) \ln f(t,x,v)$, are controlled along time. We establish quantitative estimates of \emph{propagation} in time of "pointwise polynomial moments", i.e. $\sup\_{x,v} f(t,x,v) (1+|v|)^q$, $q \ge 0$. In the case of hard potentials, we also prove \emph{appearance} of these moments for all $q \ge 0$. In the case of moderately soft potentials we prove the \emph{appearance} of low-order pointwise moments., 32 pages
Published: 2018

11. The Schauder estimate in kinetic theory with application to a toy nonlinear model

Author: Cyril Imbert, Clément Mouhot, Département de Mathématiques et Applications - ENS Paris (DMA), École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS), DPMMS/CMS, University of Cambridge [UK] (CAM), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010102 general mathematics, Mathematical analysis, Structure (category theory), Mathematics::Analysis of PDEs, Ocean Engineering, Kinetic energy, 01 natural sciences, Mathematics - Analysis of PDEs, Hypoelliptic operator, Nonlinear model, 0103 physical sciences, Kinetic theory of gases, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], 010307 mathematical physics, 0101 mathematics, Diffusion (business), Variable (mathematics)
Abstract: International audience; This article is concerned with the Schauder estimate for linear kinetic Fokker-Planck equations with Hölder continuous coefficients. This equation has an hypoelliptic structure. As an application of this Schauder estimate, we prove the global well-posedness of a toy nonlinear model in kinetic theory. This nonlinear model consists in a non-linear kinetic Fokker-Planck equation whose steady states are Maxwellian and whose diffusion in the velocity variable is proportional to the mass of the solution.
Published: 2018

12. LOFAR imaging of Cygnus A - direct detection of a turnover in the hotspot radio spectra

Author: Aris Karastergiou, Michael W. Wise, Gianni Bernardi, Heino Falcke, L. Cerrigone, D. Engels, Michel Tagger, Simona Vegetti, Anna Nelles, R. Morganti, John D. Swinbank, Leith Godfrey, George Heald, I. van Bemmel, E. Juette, P. Maat, Sera Markoff, V. I. Kondratiev, Léon V. E. Koopmans, Huib Intema, Adam Deller, H. Munk, J. W. Broderick, Marcus Brüggen, R. Blaauw, J. Sluman, M. Iacobelli, R. J. van Weeren, Roberto Pizzo, Philip Best, A. J. van der Horst, D. McKay-Bukowski, Wilfred Frieswijk, M. Pandey-Pommier, Martin J. Hardcastle, M. Pietka, Aleksandar Shulevski, Rainer Beck, Satyendra Thoudam, M. Serylak, Matthias Steinmetz, Anna M. M. Scaife, Emanuela Orrú, Antonia Rowlinson, D. D. Mulcahy, Sarod Yatawatta, H. Paas, Adam Stewart, S. Duscha, I. M. Avruch, Frank Breitling, B. Ciardi, John McKean, H. J. A. Röttgering, R. C. Vermeulen, Oleg Smirnov, Olaf Wucknitz, W. Reich, Gottfried Mann, F. de Gasperin, P. Zarka, M. Kuniyoshi, D. Rafferty, Martin Bell, Richard Fallows, James M. Anderson, G. Kuper, Mark J. Bentum, M. A. Garrett, J.-M. Grießmeier, Matthias Hoeft, Christian Vocks, M. P. van Haarlem, M. C. Toribio, A. G. Polatidis, J. van Leeuwen, Annalisa Bonafede, Rebecca McFadden, Netherlands Institute for Radio Astronomy (ASTRON), SRON Netherlands Institute for Space Research (SRON), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), University of Hertfordshire [Hatfield] (UH), Department of Astronomy and Astrophysics [PennState], Pennsylvania State University (Penn State), Penn State System-Penn State System, Department of Atmospheric and Planetary Sciences [Hampton] (APS), Hampton University, Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Université de Tours (UT), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), University of Southampton, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Edinburgh, Jacobs University [Bremen], Leibniz-Institut für Astrophysik Potsdam (AIP), Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, Hamburger Sternwarte/Hamburg Observatory, Universität Hamburg (UHH), Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud University [Nijmegen], Institute of Mathematical and Physical Sciences, Leiden Observatory [Leiden], Universiteit Leiden, Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Joint Institute for VLBI in Europe (JIVE ERIC), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Ruhr-Universität Bochum [Bochum], Oxford Astrophysics, University of Oxford, Max-Planck-Institut für Radioastronomie (MPIFR), University of Oulu, University of Groningen, Groningen, Netherlands, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Australia Telescope National Facility (ATNF), School of Physics and Astronomy [Southampton], Department of Physics and Astronomy [South Africa], University of the Western Cape (UWC), Rhodes University, Grahamstown, Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (DSMZ), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), European Project: 320745,EC:FP7:ERC,ERC-2012-ADG_20120216,RADIOLIFE(2013), Astronomy, McKean, J.P., Godfrey, L.E.H., Vegetti, S., Wise, M.W., Morganti, R., Hardcastle, M.J., Rafferty, D., Anderson, J., Avruch, I.M., Beck, R., Bell, M.E., van Bemmel, I., Bentum, M.J., Bernardi, G., Best, P., Blaauw, R., Bonafede, A., Breitling, F., Broderick, J.W., Brüggen, M., Cerrigone, L., Ciardi, B., de Gasperin, F., Deller, A., Duscha, S., Engels, D., Falcke, H., Fallows, R.A., Frieswijk, W., Garrett, M.A., Grießmeier, J.M., van Haarlem, M.P., Heald, G., Hoeft, M., van der HorstA.J., null, Iacobelli, M., Interna, H., Juette, E., Karastergiou, A., Kondratiev, V.I., Koopmans, L.V.E., Kuniyoshi, M., Kuper, G., van Leeuwen, J., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Mulcahy, D.D., Munk, H., Nelles, A., Orru, E., Paas, H., Pandey-Pommier, M., Pietka, M., Pizzo, R., Polatidis, A.G., Reich, W., Rottgering, H.J.A., Rowlinson, A., Scaife, A.M.M., Serylak, M., Shulevski, A., Sluman, J., Smirnov, O., Steinmetz, M., Stewart, A., Swinbank, J., Tagger, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., van Weeren, R.J., Wucknitz, O., Yatawatta, S., Zarka, P., High Energy Astrophys. & Astropart. Phys (API, FNWI), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Radboud university [Nijmegen], Universiteit Leiden [Leiden], Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), University of Oxford [Oxford], École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), University of the Western Cape, Smithsonian Institution-Harvard University [Cambridge], ITA, GBR, FRA, DEU, NLD, Université de Tours, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), and Harvard University [Cambridge]-Smithsonian Institution
Subjects: Radio galaxy, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Radio continuum: galaxie, Spectral line, Radio spectrum, Radio continuum: galaxies, Galaxies: active: individual: Cygnus A, X-shaped radio galaxy, 0103 physical sciences, Cygnus A, 010303 astronomy & astrophysics, Physics, Spectral index, EWI-27659, 010308 nuclear & particles physics, LOBES, Astronomy and Astrophysics, LOFAR, Astronomy and Astrophysic, Astrophysics - Astrophysics of Galaxies, Galaxy, galaxies [radio continuum], GALAXIES, METIS-321690, RESOLUTION, Space and Planetary Science, HOT-SPOTS, GAS, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, ARRAY, IR-103274
Abstract: The low-frequency radio spectra of the hotspots within powerful radio galaxies can provide valuable information about the physical processes operating at the site of the jet termination. These processes are responsible for the dissipation of jet kinetic energy, particle acceleration, and magnetic-field generation. Here we report new observations of the powerful radio galaxy Cygnus A using the Low Frequency Array (LOFAR) between 109 and 183 MHz, at an angular resolution of ~3.5 arcsec. The radio emission of the lobes is found to have a complex spectral index distribution, with a spectral steepening found towards the centre of the source. For the first time, a turnover in the radio spectrum of the two main hotspots of Cygnus A has been directly observed. By combining our LOFAR imaging with data from the Very Large Array at higher frequencies, we show that the very rapid turnover in the hotspot spectra cannot be explained by a low-energy cut-off in the electron energy distribution, as has been previously suggested. Thermal (free-free) absorption or synchrotron self absorption models are able to describe the low-frequency spectral shape of the hotspots, however, as with previous studies, we find that the implied model parameters are unlikely, and interpreting the spectra of the hotspots remains problematic., Comment: 9 pages, 3 figures, accepted for publication in MNRAS
Published: 2016

13. Cell motility in confinement: a computational model for the shape of the cell

Author: Julien Olivier, Meriem Jedouaa, Olivier Theodoly, Florence Hubert, Ariane Trescases, I. Khames, Institut de Mathématiques de Marseille (I2M), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Equations aux Dérivées Partielles (EDP ), Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Mathématiques de l'INSA de Rouen Normandie (LMI), Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU), Adhésion et Inflammation (LAI), Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Assistance Publique - Hôpitaux de Marseille (APHM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), HUBERT, Florence, and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
Subjects: Physics, T57-57.97, Applied mathematics. Quantitative methods, Microchannel, Cell, Motility, Nanotechnology, macromolecular substances, Mechanics, medicine.anatomical_structure, Cytoplasm, QA1-939, medicine, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], [MATH.MATH-AP] Mathematics [math]/Analysis of PDEs [math.AP], Lamellipodium, Mathematics
Abstract: While cells typically tend to spread their cytoplasm in a flat and thin lamellipodium when moving on a flat substrate, it is widely observed that the cytoplasm has a compact shape in micro-channels, tending to fulfill the cross-section of the microchannel. We propose a minimal mathematical model for a 2D test case which describes the cell lamellipodium deformations when confined in a channel. We then go through a numerical investigation of this mathematical model and show that it allows to recover qualitatively the physiological characteristics of the confined cell., Alors que les cellules ont généralement tendance à présenter un cytoplasme étendu en un large lamellipode extrêmement fin lors du déplacement sur un substrat plat, il est communément observé que le cytoplasme prend une forme compacte lors du déplacement dans des micro-canaux, remplissant au possible le volume contenu dans le micro-channel. Nous proposons un modèle mathématique minimal pour un cas test en 2D qui décrit les déformations du lamellipode en confinement. Nous proposons une exploration numérique de ce modèle mathématique et nous montrons qu’il permet de retrouver qualitativement les caractéristiques physiologiques de la cellule confinée.
Published: 2016

14. Long time behavior in locally activated random walks

Author: Nicolas Meunier, Clément Mouhot, Raphaël Roux, Mathématiques Appliquées Paris 5 (MAP5 - UMR 8145), Université Paris Descartes - Paris 5 (UPD5)-Institut National des Sciences Mathématiques et de leurs Interactions (INSMI)-Centre National de la Recherche Scientifique (CNRS), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire de Probabilités et Modèles Aléatoires (LPMA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Apollo - University of Cambridge Repository, DPMMS/CMS, University of Cambridge [UK] (CAM), Mathématiques Appliquées à Paris 5 ( MAP5 - UMR 8145 ), Université Paris Descartes - Paris 5 ( UPD5 ) -Institut National des Sciences Mathématiques et de leurs Interactions-Centre National de la Recherche Scientifique ( CNRS ), University of Cambridge [UK] ( CAM ), Laboratoire de Probabilités et Modèles Aléatoires ( LPMA ), and Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: Physics, Partial differential equation, dynamical transition, Applied Mathematics, General Mathematics, Probability (math.PR), non-Gaussian probability distribution, State (functional analysis), Random walk, 01 natural sciences, 010101 applied mathematics, random walk, [MATH.MATH-PR]Mathematics [math]/Probability [math.PR], local time, Local time, FOS: Mathematics, Probability distribution, Statistical physics, 0101 mathematics, Diffusion (business), [ MATH.MATH-PR ] Mathematics [math]/Probability [math.PR], Brownian motion, Mathematics - Probability, blow-up, Generator (mathematics)
Abstract: We consider a 1-dimensional Brownian motion whose diffusion coefficient varies when it crosses the origin. We study the long time behavior and we establish different regimes, depending on the variations of the diffusion coefficient: emergence of a non-Gaussian mul-tipeaked probability distribution and a dynamical transition to an absorbing static state. We compute the generator and we study the partial differential equation which involves its adjoint. We discuss global existence and blow-up of the solution to this latter equation.
Published: 2016

15. On the Cauchy Problem for the Homogeneous Boltzmann–Nordheim Equation for Bosons: Local Existence, Uniqueness and Creation of Moments

Author: Amit Einav, Marc Briant, Apollo - University of Cambridge Repository, Cambridge Center for Analysis, University of Cambridge [UK] (CAM), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and EPSRC grant EP/H023348/1 et EPSRC grant EP/L002302/1
Subjects: Boltzmann-Nordheim equation, Subcritical solutions, FOS: Physical sciences, Bose-Einstein condensation, 01 natural sciences, Bose- Einstein condensattion, symbols.namesake, [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], 0103 physical sciences, Initial value problem, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Uniqueness, 0101 mathematics, Mathematical Physics, Mathematical physics, Boson, Physics, Local Cauchy problem, 010102 general mathematics, Cauchy distribution, Statistical and Nonlinear Physics, Fermion, Mathematical Physics (math-ph), 16. Peace & justice, Boltzmann equation, Kinetic model for bosons, Distribution (mathematics), Boltzmann constant, symbols, 010307 mathematical physics
Abstract: The Boltzmann-Nordheim equation is a modification of the Boltzmann equation, based on physical considerations, that describes the dynamics of the distribution of particles in a quantum gas composed of bosons or fermions. In this work we investigate the Cauchy theory of the spatially homogeneous Boltzmann-Nordheim equation for bosons, in dimension $d\geq 3$. We show existence and uniqueness locally in time for any initial data in $L^\infty\left(1+|v|^s\right)$ with finite mass and energy, for a suitable $s$, as well as the instantaneous creation of moments of all order., Comment: 52 pages
Published: 2016

16. Ferromagnetic and antiferromagnetic order in bacterial vortex lattices

Author: Hugo Wioland, Raymond E. Goldstein, Francis G. Woodhouse, Jörn Dunkel, Institut Jacques Monod (IJM (UMR_7592)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Sorbonne Paris Cité (USPC), Department of Applied Mathematics and Theoretical Physics, University of Cambridge [UK] (CAM), Faculty of Engineering, Computing and Mathematics Australia, The University of Western Australia (UWA), Massachusetts Institute of Technology (MIT), EPSRC, MIT Solomon Buchsbaum Fund Award, Alfred P. Sloan Research Fellowship, European Project: 247333,EC:FP7:ERC,ERC-2009-AdG,BIOCOMPLEX(2010), Woodhouse, Francis Gordon [0000-0002-5305-5510], Goldstein, Raymond [0000-0003-2645-0598], Apollo - University of Cambridge Repository, Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: Thermodynamic equilibrium, Lattice field theory, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, cellular motility, Condensed Matter - Soft Condensed Matter, 01 natural sciences, Article, 0103 physical sciences, Cell Behavior (q-bio.CB), biological physics, Statistical physics, Physics - Biological Physics, 010306 general physics, Quantum, Condensed Matter - Statistical Mechanics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Statistical Mechanics (cond-mat.stat-mech), Renormalization group, 021001 nanoscience & nanotechnology, Living systems, Vortex, Coupling (physics), Biological Physics (physics.bio-ph), FOS: Biological sciences, Soft Condensed Matter (cond-mat.soft), Quantitative Biology - Cell Behavior, Spin network, 0210 nano-technology
Abstract: Despite their inherent non-equilibrium nature, living systems can self-organize in highly ordered collective states that share striking similarities with the thermodynamic equilibrium phases of conventional condensed matter and fluid systems. Examples range from the liquid-crystal-like arrangements of bacterial colonies, microbial suspensions and tissues to the coherent macro-scale dynamics in schools of fish and flocks of birds. Yet, the generic mathematical principles that govern the emergence of structure in such artificial and biological systems are elusive. It is not clear when, or even whether, well-established theoretical concepts describing universal thermostatistics of equilibrium systems can capture and classify ordered states of living matter. Here, we connect these two previously disparate regimes: Through microfluidic experiments and mathematical modelling, we demonstrate that lattices of hydrodynamically coupled bacterial vortices can spontaneously organize into distinct phases of ferro- and antiferromagnetic order. The preferred phase can be controlled by tuning the vortex coupling through changes of the inter-cavity gap widths. The emergence of opposing order regimes is tightly linked to the existence of geometry-induced edge currents, reminiscent of those in quantum systems. Our experimental observations can be rationalized in terms of a generic lattice field theory, suggesting that bacterial spin networks belong to the same universality class as a wide range of equilibrium systems., Original journal submission; revised version in press at Nature Physics. (19 pages, 8 figures)
Published: 2016

17. Charged particle signatures of the diamagnetic cavity of comet 67P/Churyumov–Gerasimenko

Author: Christoph Koenders, James L. Burch, Prachet Mokashi, Charlotte Goetz, Raymond Goldstein, H. Madanian, Kathleen Mandt, Ingo Richter, Pierre Henri, Zoltán Németh, Aniko Timar, Karoly Szego, Wigner Research Centre for Physics [Budapest], Hungarian Academy of Sciences (MTA), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Department of Physics and Astronomy [Lawrence Kansas], University of Kansas [Lawrence] (KU), UTSA Department of Physics and Astronomy [San Antonio], The University of Texas at San Antonio (UTSA), and ANR-15-CE31-0009,SPECTRA,Sonder le Plasma dans l'Environnement d'une ComètE avec RosettA(2015)
Subjects: Physics, comets: individual: 67P/Chuyumov-Gerasimenko plasmas methods: data analysis magnetic fields, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Magnetometer, Comet, Astronomy and Astrophysics, Electron, Plasma, 01 natural sciences, Charged particle, law.invention, Ion, Magnetic field, Space and Planetary Science, law, 0103 physical sciences, Diamagnetism, Atomic physics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; One of the scientific objectives of the Rosetta mission is to investigate the diamagnetic cavity of comet 67P/Churyumov–Gerasimenko. We employed combined data of several instruments of the Rosetta Plasma Consortium (RPC) to identify and study diamagnetic cavity crossing events. Using electron data from the Ion Electron Sensor (IES) to complement the Magnetometer (MAG) data enabled us to work out a search criterion for the cavity crossing events based on a unique signature we identified in the electron spectrum. Although this search criterion is insufficient to find all the cavity events, we were able to find an abundance of more than one hundred cavity crossings in the data obtained in the summer of 2015. This unexpectedly high number of events allowed us to study their common features, as well as the shape and extent of the diamagnetic cavity in the terminator plane. The results suggest that in the summer of 2015 there was a cavity around comet 67P, which had a highly variable outer boundary. We present the effects of the diamagnetic cavity on the thermal and suprathermal electron and suprathermal ion content of the plasma, and also the probable mechanisms responsible for these charged particle signatures.
Published: 2016

18. Imaging Jupiter's radiation belts down to 127 MHz with LOFAR

Author: Gianni Bernardi, Jörg R. Hörandel, A. G. Polatidis, Ashish Asgekar, A. Nelles, Angélica Sicard, H. Munk, R. J. van Weeren, Jason W. T. Hessels, D. McKay-Bukowski, I. de Pater, Matthias Hoeft, Oleg Smirnov, A. W. Gunst, Frank Breitling, Arthur Corstanje, Sebastien Hess, Quentin Nénon, Mark J. Bentum, J. van Leeuwen, R. C. Vermeulen, M. Loose, P. Zarka, H. J. A. Röttgering, P. Maat, M. J. Norden, M. Tagger, J. Moldón, F. de Gasperin, S. Bourdarie, Rene P. Breton, Annalisa Bonafede, John D. Swinbank, I. van Bemmel, Stephane Corbel, Martin Bell, V. I. Kondratiev, M. Pandey-Pommier, M. Iacobelli, James M. Anderson, Roberto Pizzo, Marcus Brüggen, Satyendra Thoudam, M. C. Toribio, Gerard H. Kuper, Antonia Rowlinson, Jochen Eislöffel, S. Duscha, Rebecca McFadden, M. A. Garrett, Daniel Santos-Costa, Julien N. Girard, Matthias Steinmetz, B. Ciardi, O. Wucknitz, J.-M. Grießmeier, M. Kuniyoshi, Ralph A. M. J. Wijers, Wilfred Frieswijk, Heino Falcke, C. Tasse, W. N. Brouw, S. Markov, Emanuela Orrú, H. Paas, Adam Deller, W. Reich, Dominik J. Schwarz, J. W. Broderick, E. Juette, G. Mann, Philip Best, C. Vocks, E. de Geus, Girard, J.N., Zarka, P., Tasse, C., Hess, S., De Pater, I., Santos-Costa, D., Nenon, Q., Sicard, A., Bourdarie, S., Anderson, J., Asgekar, A., Bell, M.E., Van Bemmel, I., Bentum, M.J., Bernardi, G., Best, P., Bonafede, A., Breitling, F., Breton, R.P., Broderick, J.W., Brouw, W.N., Brüggen, M., Ciardi, B., Corbel, S., Corstanje, A., De Gasperin, F., De Geus, E., Deller, A., Duscha, S., Eislöffel, J., Falcke, H., Frieswijk, W., Garrett, M.A., Grießmeier, J., Gunst, A.W., Hessels, J.W.T., Hoeft, M., Hörandel, J., Iacobelli, M., Juette, E., Kondratiev, V.I., Kuniyoshi, M., Kuper, G., Van Leeuwen, J., Loose, M., Maat, P., Mann, G., Markoff, S., McFadden, R., McKay-Bukowski, D., Moldon, J., Munk, H., Nelles, A., Norden, M.J., Orru, E., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A.G., Reich, W., Röttgering, H., Rowlinson, A., Schwarz, D., Smirnov, O., Steinmetz, M., Swinbank, J., Tagger, M., Thoudam, S., Toribio, M.C., Vermeulen, R., Vocks, C., Van Weeren, R.J., Wijers, R.A.M.J., Wucknitz, O., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, ONERA - The French Aerospace Lab [Toulouse], ONERA, Netherlands Institute for Radio Astronomy (ASTRON), University of Southampton, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Royal Observatory Edinburgh (ROE), University of Edinburgh, Jacobs University [Bremen], Leibniz-Institut für Astrophysik Potsdam (AIP), Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, Radboud University [Nijmegen], Hamburger Sternwarte/Hamburg Observatory, Universität Hamburg (UHH), Thüringer Landessternwarte Tautenburg (TLS), Leiden Observatory [Leiden], Universiteit Leiden, Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Ruhr-Universität Bochum [Bochum], Max-Planck-Institut für Radioastronomie (MPIFR), University of Oulu, University of Groningen [Groningen], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Universität Bielefeld, Rhodes University, Grahamstown, Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (DSMZ), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, ANR-11-IDEX-0005,USPC,Université Sorbonne Paris Cité(2011), European Project: 228261,EC:FP7:ERC,ERC-2008-AdG,SPARSEASTRO(2009), ITA, GBR, FRA, DEU, NLD, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Radboud university [Nijmegen], Universiteit Leiden [Leiden], Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Harvard University [Cambridge]-Smithsonian Institution, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Jodrell Bank Centre for Astrophysics, Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), DPMMS/CMS, University of Cambridge [UK] (CAM), ANR-11-IDEX-0005-02/10-LABX-0023,UnivEarthS,Earth - Planets - Universe: observation, modeling, transfer(2011), Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Faculty of Science
Subjects: radio continuum: planetary systems, Brightness, 010504 meteorology & atmospheric sciences, radio continuum: planetary, EWI-27447, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, FOS: Physical sciences, Astrophysics, Electron, METIS-321662, 7. Clean energy, 01 natural sciences, Jupiter, symbols.namesake, 0103 physical sciences, Emission spectrum, IR-103183, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Radio continuum: planetary system, Planets and satellites: magnetic field, Astronomy and Astrophysics, LOFAR, Astronomy and Astrophysic, planets and satellites: magnetic fields, Spectral flux density, 13. Climate action, Space and Planetary Science, Van Allen radiation belt, Techniques: interferometric, symbols, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, systems, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Context. Observing Jupiter's synchrotron emission from the Earth remains today the sole method to scrutinize the distribution and dynamical behavior of the ultra energetic electrons magnetically trapped around the planet (because in-situ particle data are limited in the inner magnetosphere). Aims. We perform the first resolved and low-frequency imaging of the synchrotron emission with LOFAR at 127 MHz. The radiation comes from low energy electrons (~1-30 MeV) which map a broad region of Jupiter's inner magnetosphere. Methods (see article for complete abstract) Results. The first resolved images of Jupiter's radiation belts at 127-172 MHz are obtained along with total integrated flux densities. They are compared with previous observations at higher frequencies and show a larger extent of the synchrotron emission source (>=4 $R_J$). The asymmetry and the dynamic of east-west emission peaks are measured and the presence of a hot spot at lambda_III=230 {\deg} $\pm$ 25 {\deg}. Spectral flux density measurements are on the low side of previous (unresolved) ones, suggesting a low-frequency turnover and/or time variations of the emission spectrum. Conclusions. LOFAR is a powerful and flexible planetary imager. The observations at 127 MHz depict an extended emission up to ~4-5 planetary radii. The similarities with high frequency results reinforce the conclusion that: i) the magnetic field morphology primarily shapes the brightness distribution of the emission and ii) the radiating electrons are likely radially and latitudinally distributed inside about 2 $R_J$. Nonetheless, the larger extent of the brightness combined with the overall lower flux density, yields new information on Jupiter's electron distribution, that may shed light on the origin and mode of transport of these particles., Comment: 10 pages, 12 figures, accepted for publication in A&A (27/11/2015) - abstract edited because of limited characters
Published: 2015

19. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes (Corrigendum)

Author: C. Sotomayor-Beltran, C. Sobey, J. W. T. Hessels, G. de Bruyn, A. Noutsos, A. Alexov, J. Anderson, A. Asgekar, I. M. Avruch, R. Beck, M. E. Bell, M. R. Bell, M. J. Bentum, G. Bernardi, P. Best, L. Birzan, A. Bonafede, F. Breitling, J. Broderick, W. N. Brouw, M. Brüggen, B. Ciardi, F. de Gasperin, R.-J. Dettmar, A. van Duin, S. Duscha, J. Eislöffel, H. Falcke, R. A. Fallows, R. Fender, C. Ferrari, W. Frieswijk, M. A. Garrett, J. Grießmeier, T. Grit, A. W. Gunst, T. E. Hassall, G. Heald, M. Hoeft, A. Horneffer, M. Iacobelli, E. Juette, A. Karastergiou, E. Keane, J. Kohler, M. Kramer, V. I. Kondratiev, L. V. E. Koopmans, M. Kuniyoshi, G. Kuper, J. van Leeuwen, P. Maat, G. Macario, S. Markoff, J. P. McKean, D. D. Mulcahy, H. Munk, E. Orru, H. Paas, M. Pandey-Pommier, M. Pilia, R. Pizzo, A. G. Polatidis, W. Reich, H. Röttgering, M. Serylak, J. Sluman, B. W. Stappers, M. Tagger, Y. Tang, C. Tasse, S. ter Veen, R. Vermeulen, R. J. van Weeren, R. A. M. J. Wijers, S. J. Wijnholds, M. W. Wise, O. Wucknitz, S. Yatawatta, P. Zarka, Astronomisches Institut der Ruhr-Universität Bochum, Ruhr-Universität Bochum [Bochum], Max-Planck-Institut für Radioastronomie (MPIFR), Netherlands Institute for Radio Astronomy (ASTRON), School of Oceanography [Seattle], University of Washington [Seattle], SRON Netherlands Institute for Space Research (SRON), Université de Tours (UT), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), University of Southampton, Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Edinburgh, Leiden Observatory [Leiden], Universiteit Leiden, Jacobs University [Bremen], Leibniz-Institut für Astrophysik Potsdam (AIP), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Max Planck Institute for Astrophysics, Hamburger Sternwarte/Hamburg Observatory, Universität Hamburg (UHH), Thüringer Landessternwarte Tautenburg (TLS), Institute of Mathematical and Physical Sciences, Department of Quantitative Methods, Università degli studi di Genova = University of Genoa (UniGe), Unité Scientifique de la Station de Nançay (USN), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jodrell Bank Centre for Astrophysics, University of Manchester [Manchester], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Oxford Astrophysics, University of Oxford, Centre for Astrophysics and Supercomputing (Centre for Astrophysics and Supercomputing), Swinburne University of Technology [Melbourne], Hessisches Landesmuseum Darmstadt, Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of Groningen, Groningen, Netherlands, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics-Electronics, Rhodes University, Grahamstown, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), SKA South Africa, Ska South Africa, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, ANR-09-JCJC-0001,OPALES(2009), European Project: 224897,EC:FP7:PEOPLE,FP7-PEOPLE-2007-2-2-ERG,WIDEMAP(2008), Université de Tours, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universiteit Leiden [Leiden], Universita degli studi di Genova, Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), University of Oxford [Oxford], Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Harvard University [Cambridge]-Smithsonian Institution, and Smithsonian Institution-Harvard University [Cambridge]
Subjects: 010504 meteorology & atmospheric sciences, Astronomy, Astrophysics, Low frequency, 01 natural sciences, Radio telescope, symbols.namesake, Optics, 0103 physical sciences, Faraday effect, 010303 astronomy & astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), 0105 earth and related environmental sciences, Physics, polarization, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, LOFAR, techniques: polarimetric, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], symbols, business, addenda, errata
Abstract: International audience; Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation contribution. We present ionFR, a code that calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. ionFR uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. We describe applications of this code for the calibration of radio polarimetric observations, and demonstrate the high accuracy of its modeled ionospheric Faraday rotations using LOFAR pulsar observations. These show that we can accurately determine some of the highest-precision pulsar rotation measures ever achieved. Precision rotation measures can be used to monitor rotation measure variations – either intrinsic or due to the changing line-of-sight through the interstellar medium. This calibration is particularly important for nearby sources, where the ionosphere can contribute a significant fraction of the observed rotation measure. We also discuss planned improvements to ionFR, as well as the importance of ionospheric Faraday rotation calibration for the emerging generation of low-frequency radio telescopes, such as the SKA and its pathfinders.
Published: 2015

20. Bosonic integer quantum Hall effect in optical flux lattices

Author: Antoine Sterdyniak, Nicolas Regnault, Nigel R. Cooper, Universität Innsbruck [Innsbruck], Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Department of Physics, Princeton University (DPPU), Princeton University, Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Cooper, Nigel [0000-0002-4662-1254], and Apollo - University of Cambridge Repository
Subjects: Physics, Chern class, General Physics and Astronomy, Conductance, FOS: Physical sciences, Quantum Hall effect, Magnetic field, Quantum spin Hall effect, Quantum Gases (cond-mat.quant-gas), Lattice (order), Quantum mechanics, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Topological order, Condensed Matter - Quantum Gases, cond-mat.quant-gas, Boson
Abstract: In two dimensions strongly interacting bosons in a magnetic field can realize a bosonic integer quantum Hall state, the simplest two dimensional example of a symmetry protected topological phase. We propose a realistic implementation of this phase using an optical flux lattice. Through exact diagonalization calculations, we show that the system exhibits a clear bulk gap and the topological signature of the bosonic integer quantum Hall state. In particular, the calculation of the many-body Chern number leads to a quantized Hall conductance in agreement with the analytical predictions. We also study the stability of the phase with respect to some of the experimentally relevant parameters., 5 pages, 6 figures
Published: 2015

21. Dynamic Optical Lattices of Subwavelength Spacing for Ultracold Atoms

Author: Nigel R. Cooper, Nathan Goldman, Jean Dalibard, Sylvain Nascimbene, Cooper, Nigel [0000-0002-4662-1254], Apollo - University of Cambridge Repository, Laboratoire Kastler Brossel (LKB (Lhomond)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire Kastler Brossel (LKB (Jussieu)), Collège de France - Chaire Atomes et rayonnement, Laboratoire Kastler Brossel (LKB [Collège de France]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Condensed matter physics, Computer simulation, FOS: Physical sciences, General Physics and Astronomy, DALIBARD Jean, Preprint/Postprint du document, Texte intégral (accès ouvert), Atomic motion, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Quantum Gases (cond-mat.quant-gas), Ultracold atom, Lattice (order), 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, Chaires, traité, Condensed Matter - Quantum Gases, Adiabatic process, Ground state, Document sous DOI (Digital Object Identifier), web-atomes-rayonnement
Abstract: We propose a scheme to realize lattice potentials of sub-wavelength spacing for ultracold atoms. It is based on spin-dependent optical lattices with a time-periodic modulation. We show that the atomic motion is well described by the combined action of an effective, time-independent, lattice of small spacing, together with a micro-motion associated with the time-modulation. A numerical simulation shows that an atomic gas can be adiabatically loaded into the effective lattice ground state, for timescales comparable to the ones required for adiabatic loading of standard optical lattices. We generalize our scheme to a two-dimensional geometry, leading to Bloch bands with non-zero Chern numbers. The realization of lattices of sub-wavelength spacing allows for the enhancement of energy scales, which could facilitate the achievment of strongly-correlated (topological) states., 10 pages, 8 figures
Published: 2015

22. Interacting bosons in topological optical flux lattices

Author: Antoine Sterdyniak, B. Andrei Bernevig, Nicolas Regnault, Nigel R. Cooper, Universität Innsbruck [Innsbruck], Department of Physics, Princeton University (DPPU), Princeton University, Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire Pierre Aigrain (LPA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Chern class, Spin states, Condensed matter physics, Energy dispersion, FOS: Physical sciences, Quantum Hall effect, Condensed Matter Physics, Topology, 3. Good health, Electronic, Optical and Magnetic Materials, Reciprocal lattice, Quantum Gases (cond-mat.quant-gas), [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Quantum mechanics, Lattice (order), Topological order, Condensed Matter - Quantum Gases, ComputingMilieux_MISCELLANEOUS, Boson
Abstract: An interesting route to the realization of topological Chern bands in ultracold atomic gases is through the use of optical flux lattices. These models differ from the tight-binding real-space lattice models of Chern insulators that are conventionally studied in solid-state contexts. Instead, they involve the coherent coupling of internal atomic (spin) states, and can be viewed as tight-binding models in reciprocal space. By changing the form of the coupling and the number $N$ of internal spin states, they give rise to Chern bands with controllable Chern number and with nearly flat energy dispersion. We investigate in detail how interactions between bosons occupying these bands can lead to the emergence of fractional quantum Hall states, such as the Laughlin and Moore-Read states. In order to test the experimental realization of these phases, we study their stability with respect to band dispersion and band mixing. We also probe novel topological phases that emerge in these systems when the Chern number is greater than 1., Comment: 14 pages, 19 figures
Published: 2015

23. Calibrating the absolute amplitude scale for air showers measured at LOFAR

Author: A. Haungs, Stijn Buitink, A. Nelles, Olaf Scholten, Oleg Smirnov, Pim Schellart, George Heald, Jörg P. Rachen, Jörg R. Hörandel, Maria Krause, A. G. Polatidis, Emanuela Orrú, Wilfred Frieswijk, H. J. A. Röttgering, W. N. Brouw, Rebecca McFadden, Frank G. Schröder, J. Kohler, Katrin Link, R. Krause, P. Zarka, M. Iacobelli, J. Sluman, P. N. Best, P. Maat, M. J. Norden, Roberto Pizzo, Satyendra Thoudam, K. Weidenhaupt, M. P. van Haarlem, M. C. Toribio, Gerard H. Kuper, J. E. Enriquez, A. Horneffer, T. Karskens, Harvey Butcher, F. de Gasperin, J. D. Bregman, S. ter Veen, R. C. Vermeulen, Jochen Eislöffel, Heino Falcke, V. I. Kondratiev, M. Pandey-Pommier, H. Paas, E. Juette, M. Bruüggen, R. Hiller, W. Reich, James M. Anderson, Stefan J. Wijnholds, R. J. van Weeren, Arthur Corstanje, A. Karastergiou, B. Ciardi, Matthias Hoeft, D. McKay-Bukowski, Laura Rossetto, O. Wucknitz, T. N. G. Trinh, S. Duscha, C. Tasse, Martin Bell, M. Serylak, Mark J. Bentum, Tim Huege, J. van Leeuwen, M. Kuniyoshi, Vishambhar Pandey, D. Carbone, Ralph A. M. J. Wijers, Dominik J. Schwarz, Richard Fallows, M. A. Garrett, L. Bähren, Martin Erdmann, Annalisa Bonafede, Physics, Astronomy and Astrophysics Research Group, Elementary Particle Physics, Radboud university [Nijmegen], Institut de Génomique Fonctionnelle de Lyon (IGFL), École normale supérieure - Lyon (ENS Lyon)-Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Karlsruher Institut für Technologie - Campus Nord, Karlsruher Institut für Technologie - Campus Süd, Netherlands Institute for Radio Astronomy (ASTRON), Department of Astrophysics [Nijmegen], Radboud university [Nijmegen]-Radboud university [Nijmegen], University of Groningen [Groningen], Global Aerospace, Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Jacobs University [Bremen], Kapteyn Astronomical Institute [Groningen], Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, Hamburger Sternwarte/Hamburg Observatory, Universität Hamburg (UHH), Thüringer Landessternwarte Tautenburg (TLS), Adran Ffiseg, Prifysgol Cymru Aberystwyth, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Joint Institute for VLBI in Europe (JIVE ERIC), DPMMS/CMS, University of Cambridge [UK] (CAM), Ruhr-Universität Bochum [Bochum], Oxford Astrophysics, University of Oxford [Oxford], Karlsruhe Institute of Technology (KIT), Max-Planck-Institut für Radioastronomie (MPIFR), University of Oulu, University of Groningen, Groningen, Netherlands, Centre de Recherche Astrophysique de Lyon (CRAL), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Department of Physics and Astronomy [South Africa], University of the Western Cape, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Aucun, Stichting WBBS, Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-École normale supérieure - Lyon (ENS Lyon), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Radboud University [Nijmegen], École normale supérieure de Lyon (ENS de Lyon)-Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Radboud University [Nijmegen]-Radboud University [Nijmegen], Universiteit Leiden, University of Oxford, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of the Western Cape (UWC), High Energy Astrophys. & Astropart. Phys (API, FNWI), Research unit Astroparticle Physics, Astronomy, and Kapteyn Astronomical Institute
Subjects: Astronomy, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Optics, Calibration, ddc:610, Instrumentation and Methods for Astrophysics (astro-ph.IM), Instrumentation, Absolute scale, ComputingMilieux_MISCELLANEOUS, Mathematical Physics, High Energy Astrophysical Phenomena (astro-ph.HE), [PHYS]Physics [physics], Physics, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, LOFAR, Amplitude, Air shower, Experimental High Energy Physics, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Antennas, Radio frequency, Antenna (radio), Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business
Abstract: Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These pulses have been measured successfully in the past few years at the LOw Frequency ARray (LOFAR) and are used to study the properties of cosmic rays. For a complete understanding of this phenomenon and the underlying physical processes, an absolute calibration of the detecting antenna system is needed. We present three approaches that were used to check and improve the antenna model of LOFAR and to provide an absolute calibration of the whole system for air shower measurements. Two methods are based on calibrated reference sources and one on a calibration approach using the diffuse radio emission of the Galaxy, optimized for short data-sets. An accuracy of 19% in amplitude is reached. The absolute calibration is also compared to predictions from air shower simulations. These results are used to set an absolute energy scale for air shower measurements and can be used as a basis for an absolute scale for the measurement of astronomical transients with LOFAR., Comment: 34 pages, 10 figures
Published: 2015

24. Subharmonic oscillations of collective molecular motors

Author: Carles Blanch-Mercader, Hermes Gadêlha, David Oriola, Jaume Casademunt, Departament ECM, Facultat de Física, Universitat de Barcelona (ECM), Universitat de Barcelona (UB), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Mathematical Institute, University of Oxford, and University of Oxford [Oxford]
Subjects: Oscillations, Differential equation, Motor proteins (myosin, chaos, General Physics and Astronomy, General theory and mathematical aspects, 01 natural sciences, 03 medical and health sciences, 87.16.Nn, 82.40.Bj, 87.10.-e, Quantum mechanics, 0103 physical sciences, Molecular motor, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, Elastic modulus, 030304 developmental biology, Physics, 0303 health sciences, kinesin dynein), Spectral density, and bifurcations, Nonlinear system, Coupling (physics), Classical mechanics, Ordinary differential equation, Reduction (mathematics)
Abstract: We study a generic two-state model for an assembly of molecular motors which is described by means of a pair of integro-partial differential equations and leads to oscillatory motion in the presence of an elastic coupling to its environment. We discuss a reduction of the system to a minimal set of three ordinary differential equations that successfully capture the complex nonlinear dynamics of the full system. In the limit of high mobility and large elastic modulus, we report on the emergence of subharmonics in the power spectrum of the oscillations. This provides a rationale for the unexplained observation of secondary peaks in a minimal actomyosin system in vitro (Placais P.-Y.et al., Phys. Rev. Lett. 103, (2009) 158102), showing that the phenomenon is robust and genuine. editor's choice Copyright c EPLA, 2014
Published: 2014

25. The evolution of a stratified turbulent cloud

Author: Stuart B. Dalziel, Nedunchezhian Swaminathan, Andrea Maffioli, Peter Davidson, Department of Engineering [Cambridge], University of Cambridge [UK] (CAM), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: Physics, Gravity (chemistry), Turbulence, business.industry, Mechanical Engineering, Energy–momentum relation, Cloud computing, Mechanics, Internal wave, Condensed Matter Physics, Kinetic energy, Atmospheric sciences, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Atmosphere, Physics::Fluid Dynamics, Mechanics of Materials, Geophysical and geological flows, Stratified turbulence, Turbulent flows, Gravity wave, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Internal waves, business
Abstract: Localized regions of turbulence, or turbulent clouds, in a stratified fluid are the subject of this study, which focuses on the edge dynamics occurring between the turbulence and the surrounding quiescent region. Through laboratory experiments and numerical simulations of stratified turbulent clouds, we confirm that the edge dynamics can be subdivided into materially driven intrusions and horizontally travelling internal wave-packets. Three-dimensional visualizations show that the internal gravity wave-packets are in fact large-scale pancake structures that grow out of the turbulent cloud into the adjacent quiescent region. The wave-packets were tracked in time, and it is found that their speed obeys the group speed relation for linear internal gravity waves. The energetics of the propagating waves, which include waveforms that are inclined with respect to the horizontal, are also considered and it is found that, after a period of two eddy turnover times, the internal gravity waves carry up to 16 % of the cloud kinetic energy into the initially quiescent region. Turbulent events in nature are often in the form of decaying turbulent clouds, and it is therefore suggested that internal gravity waves radiated from an initial cloud could play a significant role in the reorganization of energy and momentum in the atmosphere and oceans.
Published: 2014

26. Magnetic fields from inflation: The CMB temperature anisotropies

Author: Ruth Durrer, Chiara Caprini, Camille Bonvin, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Kavli Institute for Cosmology [Cambridge] (KICC), University of Cambridge [UK] (CAM), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Departement de Physique Théorique [Genève], Université de Genève = University of Geneva (UNIGE), and the Swiss National Science Foundation and the (U.S.) National Science Foundation under Grant No. NSF PHY11-25915
Subjects: Physics, Inflation (cosmology), Nuclear and High Energy Physics, Spectral index, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010308 nuclear & particles physics, Cosmic microwave background, FOS: Physical sciences, Spectral density, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Scale invariance, 01 natural sciences, General Relativity and Quantum Cosmology, Magnetic field, PACS numbers: 98.80.k, 07.55.Db, 98.80.Cq, 98.80.Es, Amplitude, Quantum mechanics, 0103 physical sciences, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], 010306 general physics, Anisotropy, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The cosmic microwave background (CMB) temperature anisotropies from primordial magnetic fields are studied. In addition to the known passive and the compensated mode we discuss an inflationary magnetic mode in the curvature perturbation, present when magnetic fields are generated during inflation. This mode is absent if the generation mechanism is causal, e.g. a phase transition. We compute and discuss the effect of this mode on the observed CMB anisotropy spectrum, in comparison with the passive and compensated ones. We find that it dominates the CMB anisotropy, and consequently leads to stronger constraints on the amplitude $B_{1\,{\rm Mpc}}$ and spectral index $n_B$ of the magnetic field than what usually found in CMB analyses from the compensated mode. This happens in particular for spectral indexes $n_B>-3$: the inflationary magnetic mode is always scale invariant, therefore through this mode even a magnetic field with a spectrum which is not scale invariant can leave a detectable signal in the CMB at large scales., 15 pages, 4 figures; v2 minor changes, matches published version
Published: 2013

27. Observation of a Strong Atom-Dimer Attraction in a Mass-Imbalanced Fermi-Fermi Mixture

Author: Jesper Levinsen, Florian Schreck, Matteo Zaccanti, Marko Cetina, Michael Jag, Dmitry S. Petrov, Rianne S. Lous, Rudolf Grimm, Institut für Quantenoptik und Quanteninformation, Institut für Experimentalphysik [Innsbruck], Universität Innsbruck [Innsbruck], Istituto Nazionale di Ottica (INO), Consiglio Nazionale delle Ricerche (CNR), Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Aarhus Institute of Advanced Studies, Aarhus University [Aarhus], and Quantum Gases & Quantum Information (WZI, IoP, FNWI)
Subjects: Physics, Condensed Matter::Quantum Gases, ultracold fermionic K-40 atoms, Condensed matter physics, [PHYS.COND.GAS]Physics [physics]/Condensed Matter [cond-mat]/Quantum Gases [cond-mat.quant-gas], Condensed Matter::Other, High Energy Physics::Lattice, Dimer, General Physics and Astronomy, FOS: Physical sciences, Fermion, 01 natural sciences, Attraction, 010305 fluids & plasmas, chemistry.chemical_compound, chemistry, Quantum Gases (cond-mat.quant-gas), 0103 physical sciences, Atom, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, 010306 general physics, Feshbach resonance, Condensed Matter - Quantum Gases, Fermi Gamma-ray Space Telescope
Abstract: We investigate a mixture of ultracold fermionic 40K atoms and weakly bound 6Li40K dimers on the repulsive side of a heteronuclear atomic Feshbach resonance. By radio-frequency spectroscopy we demonstrate that the normally repulsive atom-dimer interaction is turned into a strong attraction. The phenomenon can be understood as a three-body effect in which two heavy 40K fermions exchange the light 6Li atom, leading to attraction in odd partial-wave channels (mainly p wave). Our observations show that mass imbalance in a fermionic system can profoundly change the character of interactions as compared to the well-established mass-balanced case.
Published: 2013
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28. Inflationary dynamics with a non-Abelian gauge field

Author: Keiichi Maeda, Kei Yamamoto, Department of Physics, Waseda University, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Institute of Theoretical Astrophysics, University of oslo, Waseda University [Tokyo, Japan], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institute of Theoretical Astrophysics, University of Oslo, and University of Oslo (UiO)
Subjects: High Energy Physics - Theory, Nuclear and High Energy Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Scalar potential, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, Metric expansion of space, High Energy Physics::Theory, Theoretical physics, 0103 physical sciences, Attractor, Gauge theory, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Introduction to gauge theory, 010308 nuclear & particles physics, Scalar theories of gravitation, Classical mechanics, High Energy Physics - Theory (hep-th), Magnetic potential, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Scalar field, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We study the dynamics of the universe with a scalar field and an SU(2) non-Abelian Gauge (Yang-Mills) field. The scalar field has an exponential potential and the Yang-Mills field is coupled to the scalar field with an exponential function of the scalar field. We find that the magnetic component of the Yang-Mills field assists acceleration of the cosmic expansion and a power-law inflation becomes possible even if the scalar field potential is steep, which may be expected from some compactification of higher-dimensional unified theories of fundamental interactions. This power-law inflationary solution is a stable attractor in a certain range of coupling parameters. Unlike the case with multiple Abelian gauge fields, the power-law inflationary solution with the dominant electric component is unstable because of the existence of non-linear coupling of the Yang-Mills field. We also analyze the dynamics for the non-inflationary regime, and find several attractor solutions., 21 pages, 17 figures
Published: 2013

29. A new approach to the creation and propagation of exponential moments in the Boltzmann equation

Author: José A. Cañizo, Ricardo J. Alonso, Irene M. Gamba, Clément Mouhot, (CAAM) Rice University, Rice University [Houston], Departament de Matemàtiques [Barcelona] (UAB), Universitat Autònoma de Barcelona (UAB), Departement of Mathematics [Austin], University of Texas at Austin [Austin], Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and European Project: 279600,EC:FP7:ERC,ERC-2011-StG_20101014,MATKIT(2011)
Subjects: Physics, Integrable system, Applied Mathematics, 010102 general mathematics, Sigma, polynomial moments, exponential moments, 01 natural sciences, Boltzmann equation, Exponential function, 010101 applied mathematics, Mathematics - Analysis of PDEs, Homogeneous, Moment (physics), differential inequality, 26D10, 35A23, 76P05, 82C40, 82D10, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Beta (velocity), Povzner's estimates, 0101 mathematics, Analysis, Energy (signal processing), Mathematical physics
Abstract: We study the creation and propagation of exponential moments of solutions to the spatially homogeneous $d$-dimensional Boltzmann equation. In particular, when the collision kernel is of the form $|v-v_*|^\beta b(\cos(\theta))$ for $\beta \in (0,2]$ with $\cos(\theta)= |v-v_*|^{-1}(v-v_*)\cdot \sigma$ and $\sigma \in \mathbb{S}^{d-1}$, and assuming the classical cut-off condition $ b(\cos(\theta))$ integrable in $\mathbb{S}^{d-1}$, we prove that there exists $a > 0$ such that moments with weight $\exp(a \min{t,1} |v|^\beta)$ are finite for $t>0$, where $a$ only depends on the collision kernel and the initial mass and energy. We propose a novel method of proof based on a single differential inequality for the exponential moment with time-dependent coefficients., Comment: 14 pages. Many typos corrected in this revised version
Published: 2013

30. Early Modified Gravity: Implications for Cosmology

Author: Carsten van de Bruck, Philippe Brax, Gregory I. Sculthorpe, Anne-Christine Davis, Sebastien Clesse, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), School of Mathematics and Statistics [Sheffield] (SoMaS), University of Sheffield [Sheffield], Namur Center for Complex Systems [Namur] (NaXys), Université de Namur [Namur] (UNamur), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and ANR-2010-BLAN-0413
Subjects: High Energy Physics - Theory, Nuclear and High Energy Physics, Structure formation, Cosmology and Nongalactic Astrophysics (astro-ph.CO), General relativity, Dark matter, Cosmic microwave background, Cosmic background radiation, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, Cosmology, General Relativity and Quantum Cosmology, Theoretical physics, Big Bang nucleosynthesis, PACS numbers: 98.80.-k, 0103 physical sciences, Equivalence principle, 010306 general physics, Physics, 010308 nuclear & particles physics, [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th], Classical mechanics, High Energy Physics - Theory (hep-th), [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We study the effects of modifications of gravity after Big Bang Nucleosynthesis (BBN) which would manifest themselves mainly before recombination. We consider their effects on the Cosmic Microwave Background (CMB) radiation and on the formation of large scale structure. The models that we introduce here represent all screened modifications of General Relativity (GR) which evade the local tests of gravity such as the violation of the strong equivalence principle as constrained by the Lunar Ranging experiment. We use the tomographic description of modified gravity which defines models with screening mechanisms of the chameleon or Damour-Polyakov types and allows one to relate the temporal evolution of the mass and the coupling to matter of a scalar field to its Lagrangian and also to cosmological perturbations. The models with early modifications of gravity all involve a coupling to matter which is stronger in the past leading to effects on perturbations before recombination while minimising deviations from Lambda-CDM structure formation at late times. We find that a new family of early transition models lead to discrepancies in the CMB spectrum which could reach a few percent and appear as both enhancements and reductions of power for different scales., Comment: 22 pages, 7 figures
Published: 2013
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31. Reaching fractional quantum Hall states with optical flux lattices

Author: Jean Dalibard, Nigel R. Cooper, Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Collège de France - Chaire Atomes et rayonnement, Laboratoire Kastler Brossel (LKB [Collège de France]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Angular momentum, General Physics and Astronomy, FOS: Physical sciences, DALIBARD Jean, Pfaffian, Quantum Hall effect, Atomic species, 01 natural sciences, 010305 fluids & plasmas, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Quantum mechanics, Lattice (order), 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), traité, 010306 general physics, Electronic band structure, Boson, Physics, Condensed Matter::Quantum Gases, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Sous embargo, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Preprint/Postprint du document, 3. Good health, Quantum Gases (cond-mat.quant-gas), Chaires, Condensed Matter - Quantum Gases, Ground state, Document sous DOI (Digital Object Identifier), web-atomes-rayonnement
Abstract: http://arxiv.org/abs/1212.3552; International audience; We present a robust scheme by which fractional quantum Hall states of bosons can be achieved for ultracold atomic gases. We describe a new form of optical flux lattice, suitable for commonly used atomic species with ground state angular momentum Jg=1, for which the lowest energy band is topological and nearly dispersionless. Through exact diagonalization studies, we show that, even for moderate interactions, the many-body ground states consist of bosonic fractional quantum Hall states, including the Laughlin state and the Moore-Read (Pfaffian) state. These phases are shown to have energy gaps that are larger than temperature scales achievable in ultracold gases.
Published: 2012

32. Shallow water analogue of the standing accretion shock instability: experimental demonstration and a two-dimensional model

Author: Gilles Durand, Frédéric Masset, Thierry Foglizzo, Jérôme Guilet, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Matematicas (UNAM), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), ANR-10-BLAN-0503,SN2NS,Modélisation de l'effondrement stellaire et naissance des étoiles à neutrons et des trous noirs(2010), and ANR-06-JCJC-0119,Vortexplosion,Instabilité advective-acoustique et explosion des supernovae(2006)
Subjects: Physics, Accretion (meteorology), Shock (fluid dynamics), 010308 nuclear & particles physics, General Physics and Astronomy, Astrophysics, Mechanics, Physics - Fluid Dynamics, Physics - Popular Physics, 01 natural sciences, Instability, Laboratory experiments and apparatus, PACS numbers: 97.60.Bw, 01.50.Pa, 47.20. -k, 95.30.Lz, Neutron star, Waves and shallow water, Supernova, Supernovae, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Flow instabilities, Hydrodynamics, Symmetry breaking, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Hydraulic jump
Abstract: Despite the sphericity of the collapsing stellar core, the birth conditions of neutron stars can be highly non spherical due to a hydrodynamical instability of the shocked accretion flow. Here we report the first laboratory experiment of a shallow water analogue, based on the physics of hydraulic jumps. Both the experiment and its shallow water modeling demonstrate a robust linear instability and nonlinear properties of symmetry breaking, in a system which is one million times smaller and about hundred times slower than its astrophysical analogue., Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Letters. Supplementary Material (6 movies) available at http://irfu.cea.fr/Projets/SN2NS/outreach.html
Published: 2012

33. Atom-dimer and dimer-dimer scattering in fermionic mixtures near a narrow Feshbach resonance

Author: Jesper Levinsen, Dmitry S. Petrov, Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and National Research Center 'Kurchatov Institute' (NRC KI)
Subjects: Physics, Condensed Matter::Quantum Gases, [PHYS.COND.GAS]Physics [physics]/Condensed Matter [cond-mat]/Quantum Gases [cond-mat.quant-gas], Scattering, Dimer, Relaxation (NMR), FOS: Physical sciences, Scattering length, 01 natural sciences, Molecular physics, Resonance (particle physics), Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, chemistry.chemical_compound, chemistry, Quantum Gases (cond-mat.quant-gas), 0103 physical sciences, Atom, Bound state, Physics::Atomic and Molecular Clusters, 010306 general physics, Feshbach resonance, Condensed Matter - Quantum Gases
Abstract: We develop a diagrammatic approach for solving few-body problems in heteronuclear fermionic mixtures near a narrow interspecies Feshbach resonance. We calculate s-, p-, and d-wave phaseshifts for the scattering of an atom by a weakly-bound dimer. The fermionic statistics of atoms and the composite nature of the dimer lead to a strong angular momentum dependence of the atom-dimer interaction, which manifests itself in a peculiar interference of the scattered s- and p-waves. This effect strengthens with the mass ratio and is remarkably pronounced in 40K-(40K-6Li) atom-dimer collisions. We calculate the scattering length for two dimers formed near a narrow interspecies resonance. Finally, we discuss the collisional relaxation of the dimers to deeply bound states and evaluate the corresponding rate constant as a function of the detuning and collision energy., Comment: 16 pages, 21 figures. Submitted to EPJD, EuroQUAM special issue "Cold Quantum Matter - Achievements and Prospects"
Published: 2011

34. Quantum Monte Carlo calculation of the zero-temperature phase diagram of the two-component fermionic hard-core gas in two dimensions

Author: Richard J. Needs, Nigel R. Cooper, Neil Drummond, G. V. Shlyapnikov, Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Department of Physics [Lancaster], Lancaster University, Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Van der Waals-Zeeman Institute, University of Amsterdam [Amsterdam] (UvA), and Quantum Gases & Quantum Information (WZI, IoP, FNWI)
Subjects: Physics, Condensed Matter::Quantum Gases, Condensed matter physics, [PHYS.COND.GAS]Physics [physics]/Condensed Matter [cond-mat]/Quantum Gases [cond-mat.quant-gas], Quantum Monte Carlo, FOS: Physical sciences, Fermion, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Electronic, Optical and Magnetic Materials, Momentum, Quantum Gases (cond-mat.quant-gas), Phase (matter), 0103 physical sciences, Dynamic Monte Carlo method, Diffusion Monte Carlo, Condensed Matter - Quantum Gases, 010306 general physics, Phase diagram, Monte Carlo molecular modeling
Abstract: International audience; Motivated by potential realizations in cold-atom or cold-molecule systems, we have performed quantum Monte Carlo simulations of two-component gases of fermions in two dimensions with hard-core interactions. We have determined the gross features of the zero-temperature phase diagram, by investigating the relative stabilities of paramagnetic and ferromagnetic fluids and crystals. We have also examined the effect of including a pairwise, long-range r^(-3) potential between the particles. Our most important conclusion is that there is no region of stability for a ferromagnetic fluid phase, even if the long-range interaction is present. We also present results for the pair-correlation function, static structure factor, and momentum density of two-dimensional hard-core fluids.
Published: 2011

35. Spinor classification of the Weyl tensor in five dimensions

Author: Mahdi Godazgar, Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), and University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM)
Subjects: Physics, Weyl tensor, High Energy Physics - Theory, Pure mathematics, Ring (mathematics), Spinor, Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Type (model theory), 01 natural sciences, General Relativity and Quantum Cosmology, Connection (mathematics), symbols.namesake, High Energy Physics - Theory (hep-th), Tensor (intrinsic definition), 0103 physical sciences, Physical Sciences, symbols, Algebra over a field, Algebraic number, 010306 general physics
Abstract: We investigate the spinor classification of the Weyl tensor in five dimensions due to De Smet. We show that a previously overlooked reality condition reduces the number of possible types in the classification. We classify all vacuum solutions belonging to the most special algebraic type. The connection between this spinor and the tensor classification due to Coley, Milson, Pravda and Pravdov\'a is investigated and the relation between most of the types in each of the classifications is given. We show that the black ring is algebraically general in the spinor classification., Comment: 40 pages
Published: 2010

36. Direct dynamical coupling of spin modes and singlet Josephson supercurrent in ferromagnetic Josephson junctions

Author: Sadamichi Maekawa, Marco Aprili, Stewart E. Barnes, Ivana Petkovic, François Beuneu, Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Coral Gables], University of Miami [Coral Gables], Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), WPI Advanced Institute for Materials Research (WPI-AIMR), Tohoku University [Sendai], CREST, and Japan Science and Technology Agency
Subjects: Josephson effect, superconducting thin films, nickel alloys, 02 engineering and technology, magnetic thin films, 01 natural sciences, Pi Josephson junction, critical currents, interface magnetism, Condensed Matter::Superconductivity, ferromagnetic materials, 0103 physical sciences, superconducting materials, 010306 general physics, Spin (physics), Condensed Matter::Quantum Gases, Physics, Condensed matter physics, palladium alloys, Supercurrent, Order (ring theory), Resonance, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Coupling (probability), Electronic, Optical and Magnetic Materials, ferromagnetic resonance, Superconducting tunnel junction, Condensed Matter::Strongly Correlated Electrons, niobium, 0210 nano-technology
Abstract: Via a direct coupling between the order parameter and the singlet Josephson supercurrent we detect spin-wave resonances and their dispersion in ferromagnetic Josephson junctions in which the usual insulating or metallic barrier is replaced with a weak ferromagnet. The coupling arises within the Fraunhofer interferential description of the Josephson effect because the magnetic layer acts as a time-dependent phase plate. A spin-wave resonance at a frequency ${\ensuremath{\omega}}_{s}$ implies a dissipation that is reflected as a depression in the current-voltage curve of the Josephson junction when $\ensuremath{\hbar}{\ensuremath{\omega}}_{s}=2eV$. We have thereby performed a resonance experiment on only ${10}^{7}$ Ni atoms.
Published: 2009

37. Speckle observations with PISCO in Merate. VI. Astrometric measurements of visual binaries in 2006

Author: Robert Argyle, M. Sala, Jean-Louis Prieur, Luigi Pansecchi, Marco Scardia, INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Astronomy Survey Unit [Cambridge], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Mean squared error, Computation, Stars: binaries: close -binaries: visual -astrometry -techniques: interferometric -indi- vidual (ADS 11479, Astrophysics, ADS 16538), 01 natural sciences, law.invention, Telescope, Speckle pattern, Observatory, Position (vector), law, stars: individual (ADS 11479, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, binaries: close, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Astrometry, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], binaries: visual, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Orbit, techniques: interferometric, Space and Planetary Science, ADS 11584, astrometry
Abstract: We present relative astrometric measurements of visual binaries made during the second semester of 2006, with the speckle camera PISCO at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. We obtained 175 new measurements of 169 objects, with angular separations in the range 0″.1–4″.2, and an average accuracy of 0″.01. The mean error on the position angles is 0°.6. Most of the position angles could be determined without the usual 180° ambiguity with the application of triplecorrelation techniques and/or by inspection of the long integration files.We also present the new orbits we have computed for ADS 11479, 11584 and 16538, for which our measurements lead to large residuals and/or for which the revision was justified by the significant number of observations made since the last orbit computation (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Published: 2009

38. Speckle observations with PISCO in Merate - VII. Astrometric measurements of visual binaries in 2007

Author: M. Sala, Luigi Pansecchi, Robert Argyle, Jean-Louis Prieur, Marco Scardia, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), Astronomy Survey Unit [Cambridge], Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, Astrophysics, Astrometry, stars: individual: ADS 7871 ADS 7982 ADS 8128, Position angle, 01 natural sciences, binaries: visual, law.invention, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Telescope, Speckle pattern, Interferometry, Space and Planetary Science, Observatory, law, techniques: interferometric, 0103 physical sciences, astrometry, Speckle imaging, 010303 astronomy & astrophysics, Coronagraph
Abstract: International audience; We present relative astrometric measurements of visual binaries made during the first semester of 2007, with the Pupil Interferometry Speckle camera and COronagraph (PISCO) at the 102-cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. We obtained 226 new measurements of 214 objects, with angular separations in the range 0.15-4.5 arcsec, and an average accuracy of 0.013 arcsec. The mean error on the position angles is . Most of the position angles could be determined without the usual 180° ambiguity with the application of triple-correlation techniques and/or by inspection of the long integration files. We also present the new orbits we have computed for ADS 7871, 7982 and 8128, for which our measurements lead to large residuals and/or for which the revision is justified by the significant number of observations made since the publication of the previous orbit.
Published: 2009

39. Stability of the fermionic gases close to a p-wave Feshbach resonance

Author: Jesper Levinsen, Victor Gurarie, Nigel R. Cooper, Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Department of Physics [Boulder], and University of Colorado [Boulder]
Subjects: Physics, Condensed Matter::Quantum Gases, Condensed Matter::Other, Condensed Matter - Superconductivity, FOS: Physical sciences, Harmonic potential, Interaction energy, 01 natural sciences, Stability (probability), Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, Fermionic condensate, Superconductivity (cond-mat.supr-con), [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Superfluidity, Condensed Matter - Other Condensed Matter, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Quantum electrodynamics, 0103 physical sciences, P-wave, Atomic physics, 010306 general physics, Feshbach resonance, Hyperfine structure, Other Condensed Matter (cond-mat.other)
Abstract: International audience; We study the stability of the paired fermionic p-wave superfluid made out of identical atoms all in the same hyperfine state close to a p-wave Feshbach resonance. First we reproduce known results concerning the lifetime of a 3D superfluid, in particular, we show that it decays at the same rate as its interaction energy, thus precluding its equilibration before it decays. Then we proceed to study its stability in case when the superfluid is confined to 2D by means of an optical harmonic potential. We find that the relative stability is somewhat improved in 2D in the BCS regime, such that the decay rate is now slower than the appropriate interaction energy scale. The improvement in stability, however, is not dramatic and one probably needs to look for other mechanisms to suppress decay to create a long lived 2D p-wave fermionic superfluid.
Published: 2008

40. Pairing in ultracold Fermi gases in the lowest Landau level

Author: Th. Jolicoeur, Nicolas Regnault, Gunnar Möller, Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Condensed matter physics, Strongly Correlated Electrons (cond-mat.str-el), Condensed Matter - Mesoscale and Nanoscale Physics, Filling factor, FOS: Physical sciences, Fermion, Landau quantization, Quantum Hall effect, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, 3. Good health, Condensed Matter - Strongly Correlated Electrons, Quantum mechanics, 0103 physical sciences, Composite fermion, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quasiparticle, 11000/11, 010306 general physics, Wave function, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Spin-½
Abstract: We study a rapidly rotating gas of unpolarized spin-1/2 ultracold fermions in the two-dimensional regime when all atoms reside in the lowest Landau level. Due to the presence of the spin degree of freedom both s-wave and p-wave interactions are allowed at ultralow temperatures. We investigate the phase diagram of this system as a function of the filling factor in the lowest Landau level and in terms of the ratio between s- and p-wave interaction strengths. We show that the presence of attractive interactions induces a wide regime of phase separation with formation of maximally compact droplets that are either fully polarized or composed of spin-singlets. In the regime with no phase separation, we give evidence for fractional quantum Hall states. Most notably, we find two distinct singlet states at the filling nu =2/3 for different interactions. One of these states is accounted for by the composite fermion theory while the other one is a paired state for which we identify two competing descriptions with different topological structure. This paired state may be an Abelian liquid of composite spin-singlet Bose molecules with Laughlin correlations. Alternatively, it may be a known non-Abelian paired state, indicated by good overlaps with the corresponding trial wavefunction. By fine tuning of the scattering lengths it is possible to create the non-Abelian critical Haldane-Rezayi state for nu =1/2 and the permanent state of Moore and Read for nu =1. For purely repulsive interactions, we also find evidence for a gapped Halperin state at nu=2/5., 12 pages, 9 figs (best viewed in color), published version with additional evidence for a non-Abelian spin singlet state at filling nu=2/3
Published: 2008

41. Towards anH-theorem for granular gases

Author: Emmanuel Trizac, Thomas Rey, Clément Mouhot, P. Maynar, Stéphane Mischler, María Isabel García de Soria, Fisica Teorica, Universidad de Sevilla, CEntre de REcherches en MAthématiques de la DEcision (CEREMADE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire Paul Painlevé - UMR 8524 (LPP), Centre National de la Recherche Scientifique (CNRS)-Université de Lille, Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Paul Painlevé (LPP), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Reliable numerical approximations of dissipative systems (RAPSODI ), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Inria Lille - Nord Europe, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Inria Lille - Nord Europe, and Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear
Subjects: Statistics and Probability, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], FOS: Physical sciences, 01 natural sciences, Kinetic theory of gases and liquids, 010305 fluids & plasmas, Molecular dynamics, symbols.namesake, 0103 physical sciences, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Statistical physics, [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech], 010306 general physics, Condensed Matter - Statistical Mechanics, Mathematical Physics, Physics, Statistical Mechanics (cond-mat.stat-mech), H-theorem, Statistical and Nonlinear Physics, Mathematical Physics (math-ph), Elastic collision, Distribution (mathematics), Boltzmann constant, Dissipative system, symbols, Direct simulation Monte Carlo, Statistics, Probability and Uncertainty, Spectral method
Abstract: 14 pages, 5 figures; International audience; The H-theorem, originally derived at the level of Boltzmann non-linear kinetic equation for a dilute gas undergoing elastic collisions, strongly constrains the velocity distribution of the gas to evolve irreversibly towards equilibrium. As such, the theorem could not be generalized to account for dissipative systems: the conservative nature of collisions is an essential ingredient in the standard derivation. For a dissipative gas of grains, we construct here a simple functional H related to the original H, that can be qualified as a Lyapunov functional. It is positive, and results backed by three independent simulation approaches (a deterministic spectral method, the stochastic Direct Simulation Monte Carlo technique, and Molecular Dynamics) indicate that it is also non-increasing. Both driven and unforced cases are investigated.
Published: 2015

42. Asymptotic behavior of the Rayleigh-Taylor instability

Author: Christophe Josserand, Laurent Duchemin, Paul Clavin, Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de modélisation en mécanique (LMM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Department of Applied Mathematics and Theoretical Physics [Cambridge] (DAMTP), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), and Hannoun, Judith
Subjects: General Physics and Astronomy, FOS: Physical sciences, [SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Curvature, 01 natural sciences, Instability, 010305 fluids & plasmas, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], Physics::Fluid Dynamics, Acceleration, Atwood number, Inviscid flow, 0103 physical sciences, Fluid dynamics, Overshoot (signal), boundary integral equations, [PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Rayleigh–Taylor instability, Rayleigh-Taylor instability, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], 010306 general physics, Physics, asymptotic stability, Mathematical analysis, Fluid Dynamics (physics.flu-dyn), Physics - Fluid Dynamics, flow simulation
Abstract: We investigate long time numerical simulations of the inviscid Rayleigh-Taylor instability at Atwood number one using a boundary integral method. We are able to attain the asymptotic behavior for the spikes predicted by Clavin & Williams\cite{clavin} for which we give a simplified demonstration. In particular we observe that the spike's curvature evolves like $t^3$ while the overshoot in acceleration shows a good agreement with the suggested $1/t^5$ law. Moreover, we obtain consistent results for the prefactor coefficients of the asymptotic laws. Eventually we exhibit the self-similar behavior of the interface profile near the spike., 4 pages, 6 figures
Published: 2005

43. THE WIGNER–FOKKER–PLANCK EQUATION: STATIONARY STATES AND LARGE TIME BEHAVIOR

Author: Christof Sparber, Maria Pia Gualdani, Irene M. Gamba, Clément Mouhot, Anton Arnold, Stéphane Mischler, Institut für Analysis und Scientific Computing, Vienna University of Technology (TU Wien), Departement of Mathematics [Austin], University of Texas at Austin [Austin], CEntre de REcherches en MAthématiques de la DEcision (CEREMADE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Dauphine-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Pure Mathematics and Mathematical Statistics (DPMMS), Faculty of mathematics Centre for Mathematical Sciences [Cambridge] (CMS), University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Department of Mathematics, Statistics and Computer Science [Chicago] (UIC), University of Illinois [Chicago] (UIC), University of Illinois System-University of Illinois System, Institut für Numerische und Angewandte Mathematik, Westfälische Wilhelms-Universität Münster (WWU), Mathematics department, George Washington University, and The George Washington University (GW)
Subjects: Density matrix, Trace (linear algebra), Spectral gap, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], 01 natural sciences, 82C10, 35S10,74H40, 81Q15, Wigner transform, Operator (computer programming), [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], [MATH.MATH-MP]Mathematics [math]/Mathematical Physics [math-ph], [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP], Large time behavior, 0101 mathematics, Harmonic oscillator, Stationary solution, Physics, Applied Mathematics, 010102 general mathematics, Mathematical analysis, Fokker Planck operator, 010101 applied mathematics, Sobolev space, Modeling and Simulation, Fokker–Planck equation, Stationary state
Abstract: We consider the linear Wigner–Fokker–Planck equation subject to confining potentials which are smooth perturbations of the harmonic oscillator potential. For a certain class of perturbations we prove that the equation admits a unique stationary solution in a weighted Sobolev space. A key ingredient of the proof is a new result on the existence of spectral gaps for Fokker–Planck type operators in certain weighted L2-spaces. In addition we show that the steady state corresponds to a positive density matrix operator with unit trace and that the solutions of the time-dependent problem converge towards the steady state with an exponential rate.
Published: 2012

44. Stable topological superfluid phase of ultracold polar fermionic molecules

Author: Nigel R. Cooper, G. V. Shlyapnikov, Theory of Condensed Matter Group (TCM), Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Van der Waals-Zeeman Institute, University of Amsterdam [Amsterdam] (UvA), and Quantum Gases & Quantum Information (WZI, IoP, FNWI)
Subjects: Physics, [PHYS.COND.GAS]Physics [physics]/Condensed Matter [cond-mat]/Quantum Gases [cond-mat.quant-gas], Strongly Correlated Electrons (cond-mat.str-el), Field (physics), Condensed matter physics, FOS: Physical sciences, General Physics and Astronomy, Order (ring theory), Fermion, Topology, 01 natural sciences, 010305 fluids & plasmas, Superfluidity, Condensed Matter - Strongly Correlated Electrons, Dipole, Quantum Gases (cond-mat.quant-gas), Pairing, Phase (matter), 0103 physical sciences, Quantum information, Condensed Matter - Quantum Gases, 010306 general physics
Abstract: We show that single-component fermionic polar molecules confined to a 2D geometry and dressed by a microwave field may acquire an attractive $1/{r}^{3}$ dipole-dipole interaction leading to superfluid $p$-wave pairing at sufficiently low temperatures even in the BCS regime. The emerging state is the topological ${p}_{x}+i{p}_{y}$ phase promising for topologically protected quantum information processing. The main decay channel is via collisional transitions to dressed states with lower energies and is rather slow, setting a lifetime of the order of seconds at 2D densities $\ensuremath{\sim}{10}^{8}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$.
Published: 2009

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