Search

Your search keyword '"K. Giesel"' showing total 12 results
Start Over Author "K. Giesel"
12 results on '"K. Giesel"'

1. Quantum gravity phenomenology at the dawn of the multi-messenger era—A review

Author

A. Addazi, J. Alvarez-Muniz, R. Alves Batista, G. Amelino-Camelia, V. Antonelli, M. Arzano, M. Asorey, J.-L. Atteia, S. Bahamonde, F. Bajardi, A. Ballesteros, B. Baret, D.M. Barreiros, S. Basilakos, D. Benisty, O. Birnholtz, J.J. Blanco-Pillado, D. Blas, J. Bolmont, D. Boncioli, P. Bosso, G. Calcagni, S. Capozziello, J.M. Carmona, S. Cerci, M. Chernyakova, S. Clesse, J.A.B. Coelho, S.M. Colak, J.L. Cortes, S. Das, V. D’Esposito, M. Demirci, M.G. Di Luca, A. di Matteo, D. Dimitrijevic, G. Djordjevic, D. Dominis Prester, A. Eichhorn, J. Ellis, C. Escamilla-Rivera, G. Fabiano, S.A. Franchino-Viñas, A.M. Frassino, D. Frattulillo, S. Funk, A. Fuster, J. Gamboa, A. Gent, L.Á. Gergely, M. Giammarchi, K. Giesel, J.-F. Glicenstein, J. Gracia-Bondía, R. Gracia-Ruiz, G. Gubitosi, E.I. Guendelman, I. Gutierrez-Sagredo, L. Haegel, S. Heefer, A. Held, F.J. Herranz, T. Hinderer, J.I. Illana, A. Ioannisian, P. Jetzer, F.R. Joaquim, K.-H. Kampert, A. Karasu Uysal, T. Katori, N. Kazarian, D. Kerszberg, J. Kowalski-Glikman, S. Kuroyanagi, C. Lämmerzahl, J. Levi Said, S. Liberati, E. Lim, I.P. Lobo, M. López-Moya, G.G. Luciano, M. Manganaro, A. Marcianò, P. Martín-Moruno, Manel Martinez, Mario Martinez, H. Martínez-Huerta, P. Martínez-Miravé, M. Masip, D. Mattingly, N. Mavromatos, A. Mazumdar, F. Méndez, F. Mercati, S. Micanovic, J. Mielczarek, A.L. Miller, M. Milosevic, D. Minic, L. Miramonti, V.A. Mitsou, P. Moniz, S. Mukherjee, G. Nardini, S. Navas, M. Niechciol, A.B. Nielsen, N.A. Obers, F. Oikonomou, D. Oriti, C.F. Paganini, S. Palomares-Ruiz, R. Pasechnik, V. Pasic, C. Pérez de los Heros, C. Pfeifer, M. Pieroni, T. Piran, A. Platania, S. Rastgoo, J.J. Relancio, M.A. Reyes, A. Ricciardone, M. Risse, M.D. Rodriguez Frias, G. Rosati, D. Rubiera-Garcia, H. Sahlmann, M. Sakellariadou, F. Salamida, E.N. Saridakis, P. Satunin, M. Schiffer, F. Schüssler, G. Sigl, J. Sitarek, J. Solà Peracaula, C.F. Sopuerta, T.P. Sotiriou, M. Spurio, D. Staicova, N. Stergioulas, S. Stoica, J. Strišković, T. Stuttard, D. Sunar Cerci, Y. Tavakoli, C.A. Ternes, T. Terzić, T. Thiemann, P. Tinyakov, M.D.C. Torri, M. Tórtola, C. Trimarelli, T. Trześniewski, A. Tureanu, F.R. Urban, E.C. Vagenas, D. Vernieri, V. Vitagliano, J.-C. Wallet, J.D. Zornoza, Addazi, A., Alvarez-Muniz, J., Alves Batista, R., Amelino-Camelia, G., Antonelli, V., Arzano, M., Asorey, M., Atteia, J. -L., Bahamonde, S., Bajardi, F., Ballesteros, A., Baret, B., Barreiros, D. M., Basilakos, S., Benisty, D., Birnholtz, O., Blanco-Pillado, J. J., Blas, D., Bolmont, J., Boncioli, D., Bosso, P., Calcagni, G., Capozziello, S., Carmona, J. M., Cerci, S., Chernyakova, M., Clesse, S., Coelho, J. A. B., Colak, S. M., Cortes, J. L., Das, S., D'Esposito, V., Demirci, M., Di Luca, M. G., di Matteo, A., Dimitrijevic, D., Djordjevic, G., Prester, D. D., Eichhorn, A., Ellis, J., Escamilla-Rivera, C., Fabiano, G., Franchino-Vinas, S. A., Frassino, A. M., Frattulillo, D., Funk, S., Fuster, A., Gamboa, J., Gent, A., Gergely, L. A., Giammarchi, M., Giesel, K., Glicenstein, J. -F., Gracia-Bondia, J., Gracia-Ruiz, R., Gubitosi, G., Guendelman, E. I., Gutierrez-Sagredo, I., Haegel, L., Heefer, S., Held, A., Herranz, F. J., Hinderer, T., Illana, J. I., Ioannisian, A., Jetzer, P., Joaquim, F. R., Kampert, K. -H., Uysal, A. K., Katori, T., Kazarian, N., Kerszberg, D., Kowalski-Glikman, J., Kuroyanagi, S., Lammerzahl, C., Said, J. L., Liberati, S., Lim, E., Lobo, I. P., Lopez-Moya, M., Luciano, G. G., Manganaro, M., Marciano, A., Martin-Moruno, P., Martinez, M., Martinez-Huerta, H., Martinez-Mirave, P., Masip, M., Mattingly, D., Mavromatos, N., Mazumdar, A., Mendez, F., Mercati, F., Micanovic, S., Mielczarek, J., Miller, A. L., Milosevic, M., Minic, D., Miramonti, L., Mitsou, V. A., Moniz, P., Mukherjee, S., Nardini, G., Navas, S., Niechciol, M., Nielsen, A. B., Obers, N. A., Oikonomou, F., Oriti, D., Paganini, C. F., Palomares-Ruiz, S., Pasechnik, R., Pasic, V., Perez de los Heros, C., Pfeifer, C., Pieroni, M., Piran, T., Platania, A., Rastgoo, S., Relancio, J. J., Reyes, M. A., Ricciardone, A., Risse, M., Frias, M. D. R., Rosati, G., Rubiera-Garcia, D., Sahlmann, H., Sakellariadou, M., Salamida, F., Saridakis, E. N., Satunin, P., Schiffer, M., Schussler, F., Sigl, G., Sitarek, J., Peracaula, J. S., Sopuerta, C. F., Sotiriou, T. P., Spurio, M., Staicova, D., Stergioulas, N., Stoica, S., Striskovic, J., Stuttard, T., Cerci, D. S., Tavakoli, Y., Ternes, C. A., Terzic, T., Thiemann, T., Tinyakov, P., Torri, M. D. C., Tortola, M., Trimarelli, C., Trzesniewski, T., Tureanu, A., Urban, F. R., Vagenas, E. C., Vernieri, D., Vitagliano, V., Wallet, J. -C., Zornoza, J. D., AstroParticule et Cosmologie (APC (UMR_7164)), 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)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), A. Addazi, J. Alvarez-Muniz, R. Alves Batista, G. Amelino-Camelia, V. Antonelli, M. Arzano, M. Asorey, J.-L. Atteia, S. Bahamonde, F. Bajardi, A. Ballestero, B. Baret, D.M. Barreiro, S. Basilako, D. Benisty, O. Birnholtz, J.J. Blanco-Pillado, D. Bla, J. Bolmont, D. Boncioli, P. Bosso, G. Calcagni, S. Capozziello, J.M. Carmona, S. Cerci, M. Chernyakov, S. Clesse, J.A.B. Coelho, S.M. Colak, J.L. Corte, S. Da, V. D???Esposito, M. Demirci, M.G. Di Luca, A. di Matteo, D. Dimitrijevic, G. Djordjevic, D. Dominis Prester, A. Eichhorn, J. Elli, C. Escamilla-Rivera, G. Fabiano, S.A. Franchino-Vi??a, A.M. Frassino, D. Frattulillo, S. Funk, A. Fuster, J. Gamboa, A. Gent, L.??. Gergely, M. Giammarchi, K. Giesel, J.-F. Glicenstein, J. Gracia-Bond??a, R. Gracia-Ruiz, G. Gubitosi, E.I. Guendelman, I. Gutierrez-Sagredo, L. Haegel, S. Heefer, A. Held, F.J. Herranz, T. Hinderer, J.I. Illana, A. Ioannisian, P. Jetzer, F.R. Joaquim, K.-H. Kampert, A. Karasu Uysal, T. Katori, N. Kazarian, D. Kerszberg, J. Kowalski-Glikman, S. Kuroyanagi, C. L??mmerzahl, J. Levi Said, S. Liberati, E. Lim, I.P. Lobo, M. L??pez-Moya, G.G. Luciano, M. Manganaro, A. Marcian??, P. Mart??n-Moruno, Manel Martinez, Mario Martinez, H. Mart??nez-Huerta, P. Mart??nez-Mirav??, M. Masip, D. Mattingly, N. Mavromato, A. Mazumdar, F. M??ndez, F. Mercati, S. Micanovic, J. Mielczarek, A.L. Miller, M. Milosevic, D. Minic, L. Miramonti, V.A. Mitsou, P. Moniz, S. Mukherjee, G. Nardini, S. Nava, M. Niechciol, A.B. Nielsen, N.A. Ober, F. Oikonomou, D. Oriti, C.F. Paganini, S. Palomares-Ruiz, R. Pasechnik, V. Pasic, C. P??rez de los Hero, C. Pfeifer, M. Pieroni, T. Piran, A. Platania, S. Rastgoo, J.J. Relancio, M.A. Reye, A. Ricciardone, M. Risse, M.D. Rodriguez Fria, G. Rosati, D. Rubiera-Garcia, H. Sahlmann, M. Sakellariadou, F. Salamida, E.N. Saridaki, P. Satunin, M. Schiffer, F. Sch??ssler, G. Sigl, J. Sitarek, J. Sol?? Peracaula, C.F. Sopuerta, T.P. Sotiriou, M. Spurio, D. Staicova, N. Stergioula, S. Stoica, J. Stri??kovi??, T. Stuttard, D. Sunar Cerci, Y. Tavakoli, C.A. Terne, T. Terzi??, T. Thiemann, P. Tinyakov, M.D.C. Torri, M. T??rtola, C. Trimarelli, T. Trze??niewski, A. Tureanu, F.R. Urban, E.C. Vagena, D. Vernieri, V. Vitagliano, J.-C. Wallet, J.D. Zornoza, Laboratoire de Physique Théorique d'Orsay [Orsay] (LPT), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Generalitat de Catalunya, European Commission, Xunta de Galicia, Ministerio de Economía y Competitividad (España), European Research Council, Eusko Jaurlaritza, Generalitat Valenciana, Japan Society for the Promotion of Science, and Comunidad de Madrid

Subjects
High Energy Physics - Theory, CAUSAL DYNAMICAL TRIANGULATIONS, Ultra-high-energy cosmic rays, [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], Lorentz invariance violation and deformation, Gamma-ray astronomy, Cosmic neutrinos, Gravitational waves, General Relativity and Quantum Cosmology, Lorentz transformations, Gravitational waves -- Detection, High Energy Physics - Phenomenology (hep-ph), Astronomi, astrofysik och kosmologi, Gamma ray astronomy, Astronomy, Astrophysics and Cosmology, Cosmic neutrino, astro-ph.HE, High Energy Astrophysical Phenomena (astro-ph.HE), General Relativity and Cosmology, hep-th, hep-ph, Quantum cosmology, ENERGY COSMIC-RAYS, High Energy Physics - Phenomenology, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], Neutrinos -- Scattering, Astrophysics - High Energy Astrophysical Phenomena, Particle Physics - Theory, Gravitational wave, ACTIVE GALACTIC NUCLEI, Astrophysics and Astronomy, Nuclear and High Energy Physics, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], gr-qc, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), GAMMA-RAY BURST, DOUBLY-SPECIAL RELATIVITY, Ultra-high-energy cosmic ray, Particle Physics - Phenomenology, PRIMORDIAL BLACK-HOLES, Matematikk og Naturvitenskap: 400::Fysikk: 430 [VDP], COHERENT STATES GCS, Quantum gravity, GENERALIZED UNCERTAINTY PRINCIPLE, EXTRAGALACTIC BACKGROUND LIGHT, High Energy Physics - Theory (hep-th), [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], LORENTZ INVARIANCE VIOLATION
Abstract

The exploration of the universe has recently entered a new era thanks to the multimessenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic messengers (photons, neutrinos, cosmic rays and gravitational waves) from numerous origins. They give us information about their sources in the universe and the properties of the intergalactic medium. Moreover, multi-messenger astronomy opens up the possibility to search for phenomenological signatures of quantum gravity. On the one hand, the most energetic events allow us to test our physical theories at energy regimes which are not directly accessible in accelerators; on the other hand, tiny effects in the propagation of very high energy particles could be amplified by cosmological distances. After decades of merely theoretical investigations, the possibility of obtaining phenomenological indications of Planck-scale effects is a revolutionary step in the quest for a quantum theory of gravity, but it requires cooperation between different communities of physicists (both theoretical and experimental). This review, prepared within the COST Action CA18108 ‘‘Quantum gravity phenomenology in the multi-messenger approach", is aimed at promoting this cooperation by giving a state-of-the art account of the interdisciplinary expertise that is needed in the effective search of quantum gravity footprints in the production, propagation and detection of cosmic messengers., Talent Scientific Research Program of College of Physics, Sichuan University 1082204112427, Fostering Program in Disciplines Possessing Novel Features for Natural Science of Sichuan University 2020SCUNL209, 1000 Talent program of Sichuan province 2021, Xunta de Galicia, European Commission European Union ERDF, "Maria de Maeztu'' Units of Excellence program MDM-2016-0692, Red Tematica Nacional de Astroparticulas RED2018-102661-T, La Caixa Foundation 100010434, European Commission 847648 LCF/BQ/PI21/11830030 754510, Ministry of Education, Science & Technological Development, Serbia 451-03-9/2021-14/200124, FSR Incoming Postdoctoral Fellowship Ministry of Education, Science and Technological Development, Serbia 451-03-9/2021-14/200124, University of Rijeka grant uniri-prirod-18-48, Croatian Science Foundation (HRZZ) IP-2016-06-9782, Villum Fonden 29405 DGA-FSE 2020-E2117R, European Regional Development Fund through the Center of Excellence (TK133) "The Dark Side of the Universe'' European Regional Development Fund (ESIF/ERDF), Ministry of Education, Youth & Sports - Czech Republic CoGraDS-CZ.02.1.01/0.0/0.0/15 003/0000437, Blavatnik grant, Basque Government IT-97916 Basque Foundation for Science (IKERBASQUE), European Space Agency C4000120711 4000132310, FNRS (Belgian Fund for Research), Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT), Universidad Nacional Autonoma de Mexico TA100122, National University of La Plata X909 DICYT 042131GR, National Research, Development & Innovation Office (NRDIO) - Hungary 123996, FQXi, Swiss National Science Foundation (SNSF), European Commission 181461 199307, Netherlands Organization for Scientific Research (NWO) 680-91-119 15MV71, Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (KAKENHI) 20H01899 20H05853 JP21F21789, Estonian Research Council PRG356, Julian Schwinger Foundation, Generalitat Valenciana Excellence PROMETEO-II/2017/033 PROMETEO/2018/165, Istituto Nazionale di Fisica Nucleare (INFN), European ITN project HIDDeN H2020-MSCA-ITN-2019//860881-HIDDeN, Swedish Research Council, European Commission 2016-05996 European Research Council (ERC) European Commission 668679, Advanced ERC grant TReX, Ministry of Education, Universities and Research (MIUR) 2017X7X85K, Fonds de la Recherche Scientifique - FNRS 4.4501.18, Ministry of Research, Innovation and Digitization - Romania PN19-030102-INCDFM PN-III-P4ID-PCE-2020-2374, United States Department of Energy (DOE) DE-SC0020262, Ministry of Science, ICT & Future Planning, Republic of Korea 075-15-2020-778, German Academic Scholarship Foundation German Research Foundation (DFG) 408049454 420243324 425333893 445990517 Germany's Excellence Strategy (EXC 2121 "Quantum Universe'') 390833306 390837967 Federal Ministry of Education & Research (BMBF) 05 A20GU2 05 A20PX1, Centro de Excelencia "Severo Ochoa'' SEV-2016-0588, CERCA program of the Generalitat de Catalunya, Agencia de Gestio D'Ajuts Universitaris de Recerca Agaur (AGAUR) Generalitat de Catalunya 2017-SGR-1469 2017-SGR-929 ICCUB CEX2019-000918-M, National Science Centre, Poland 2019/33/B/ST2/00050 2017/27/B/ST2/01902, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 306414/2020-1, Dicyt-USACH 041931MF, National Science Fund of Bulgaria KP-06-N 38/11 RCN ROMFORSK 302640, Comunidad de Madrid 2018-T1/TIC-10431 2019-T1/TIC-13177 S2018/NMT-4291, UK Research & Innovation (UKRI), Science & Technology Facilities Council (STFC) ST/T000759/1 ST/P000258/1 ST/T000732/1 ST/V005596/1, Portuguese Foundation for Science and Technology UIDB/00618/2020 UIDB/00777/2020 UIDP/00777/2020 CERN/FIS-PAR/0004/2019 PTDC/FIS-PAR/29436/2017 PTDC/FISPAR/31938/2017 PTDC/FIS-OUT/29048/2017 SFRH/BD/137127/2018, Centre National de la Recherche Scientifique (CNRS), LabEx UnivEarthS ANR-10-LABX-0023 ANR18-IDEX-0001, Junta de Andalucia European Commission A-FQM-053-UGR18, Natural Sciences and Engineering Research Council of Canada (NSERC) RGPIN-2021-03644, National Science Centre Poland Sonata Bis 2019/33/B/ST2/00050 DEC-2017/26/E/ST2/00763, Natural Sciences and Engineering Research Council of Canada (NSERC) DGIID-DGA 2015-E24/2, Spanish Research State Agency and Ministerio de Ciencia e Innovacion MCIN/AEI PID2019-104114RB-C32 PID2019-105544GB-I00 PID2019-105614GB-C21 PID2019106515GB-I00 PID2019-106802GB-I00 PID2019-107394GB-I00 PID2019-107844GB-C21 PID2019-107847RB-C41 MCIN/AEI PGC2018-095328-B-I00 PGC2018-094856-B-I00 PGC2018-096663-B-C41 PGC2018-096663-B-C44 PGC2018-094626-BC21 PGC2018-101858-B-I00 FPA2017-84543-P FPA2016-76005-C2-1-P, Spanish 'Ministerio de Universidades' BG20/00228 Spanish Government PID2020-115845GBI00 Generalitat de Catalunya Comunidad de Madrid S2018/NMT-4291 Spanish Government PID2019-105544GB-I00, Perimeter Institute for Theoretical Physics, Government of Canada through the Department of Innovation, Science and Economic Development, Province of Ontario through the Ministry of Colleges and Universities, Centre National de la Recherche Scientifique (CNRS), Netherlands Organization for Scientific Research (NWO), Fundamental Questions Institute (FQXi), European Cooperation in Science and Technology (COST) CA18108, Research Council of University of Guilan, Iniziativa Specifica TEONGRAV Iniziativa Specifica QGSKY Iniziativa Specifica QUAGRAP Iniziativa Specifica GeoSymQFT, the Spanish Research State Agency and Ministerio de Ciencia e Innovacion MCIN/AEI PID2020-115845GBI00 PID2019-108485GB-I00 PID2020-113334GB-I00 PID2020-113701GB-I00 PID2020-113775GB-I00 PID2020-118159GB-C41 PID2020-118159GA-C42 PRE2019-089024, Rothchild grant UID/MAT/00212/2020 FPU18/04571

Published
2022
Full Text
View/download PDF

4. Algebraic Quantum Gravity (AQG) IV. Reduced Phase Space Quantisation of Loop Quantum Gravity

Author

K. Giesel and T. Thiemann

Subjects
Physics, High Energy Physics - Theory, Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, General relativity, Hilbert space, FOS: Physical sciences, Observable, Loop quantum gravity, General Relativity and Quantum Cosmology (gr-qc), Linear-quadratic-Gaussian control, 01 natural sciences, General Relativity and Quantum Cosmology, symbols.namesake, High Energy Physics - Theory (hep-th), Phase space, 0103 physical sciences, symbols, Quantum gravity, 010306 general physics, Hamiltonian (quantum mechanics), Mathematical physics
Abstract

We perform a canonical, reduced phase space quantisation of General Relativity by Loop Quantum Gravity (LQG) methods. The explicit construction of the reduced phase space is made possible by the combination of 1. the Brown -- Kuchar mechanism in the presence of pressure free dust fields which allows to deparametrise the theory and 2. Rovelli's relational formalism in the extended version developed by Dittrich to construct the algebra of gauge invariant observables. Since the resulting algebra of observables is very simple, one can quantise it using the methods of LQG. Basically, the kinematical Hilbert space of non reduced LQG now becomes a physical Hilbert space and the kinematical results of LQG such as discreteness of spectra of geometrical operators now have physical meaning. The constraints have disappeared, however, the dynamics of the observables is driven by a physical Hamiltonian which is related to the Hamiltonian of the standard model (without dust) and which we quantise in this paper., 31 pages, no figures

Published
2007

5. Cosmic UHE Neutrino Signatures

Author

E. Reya, K. Giesel, and J. H. Jureit

Subjects
Physics, Particle physics, COSMIC cancer database, Neutral current, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), High Energy Physics::Phenomenology, FOS: Physical sciences, Astronomy and Astrophysics, Parton, Astrophysics, Air shower, Radiative transfer, High Energy Physics::Experiment, Neutrino, Event (particle physics), Energy (signal processing)
Abstract

Utilizing the unique and reliable ultrasmall--$x$ predictions of the dynamical (radiative) parton model, nominal event rates and their detailed energy dependence caused by a variety of cosmic UHE neutrino fluxes are calculated and analyzed. In addition, maximal Regge--model inspired small--$x$ structure functions are employed for obtaining optimal rates which do not necessarily require `new' physics interpretations. Upward $��^+ +��^-$ event rates are estimated by taking into account total and nadir--angle dependent regeneration effects due to neutral current interactions. For exploring extragalactic neutrino sources at highest energies (\raisebox{-0.1cm}{$\stackrel{>}{\sim}$} $10^8$ GeV) with modern (future) ground--level telescopes, we analyze horizontal air shower event rates and shower events caused by Earth--skimming tau--neutrinos, in particular their detailed shower-- and cosmic neutrino--energy dependence. As an illustration of `new physics' implications we estimate the relevant horizontal air shower event rates due to spin--2 Kaluza--Klein `graviton' exchanges in neutral current neutrino--quark and neutrino--gluon interactions at low TeV--scales., 3 figures changed, discussions and references added

Published
2003

6. Algebraic quantum gravity (AQG): I. Conceptual setup.

Author

K Giesel and T Thiemann

Subjects
*QUANTUM theory, *GENERAL relativity (Physics), *QUANTUM gravity, *ASTRONOMICAL perturbation
Abstract

We introduce a new top down approach to canonical quantum gravity, called algebraic quantum gravity (AQG). The quantum kinematics of AQG is determined by an abstract *-algebra generated by a countable set of elementary operators labelled by an algebraic graph. The quantum dynamics of AQG is governed by a single master constraint operator. While AQG is inspired by loop quantum gravity (LQG), it differs drastically from it because in AQG there is fundamentally no topology or differential structure. A natural Hilbert space representation acquires the structure of an infinite tensor product (ITP) whose separable strong equivalence class Hilbert subspaces (sectors) are left invariant by the quantum dynamics. The missing information about the topology and differential structure of the spacetime manifold as well as about the background metric to be approximated is supplied by coherent states. Given such data, the corresponding coherent state defines a sector in the ITP which can be identified with a usual QFT on the given manifold and background. Thus, AQG contains QFT on all curved spacetimes at once, possibly has something to say about topology change and provides the contact with the familiar low energy physics. In particular, in two companion papers we develop semiclassical perturbation theory for AQG and LQG and thereby show that the theory admits a semiclassical limit whose infinitesimal gauge symmetry agrees with that of general relativity. In AQG everything is computable with sufficient precision and no UV divergences arise due to the background independence of the fundamental combinatorial structure. Hence, in contrast to lattice gauge theory on a background metric, no continuum limit has to be taken. There simply is no lattice regulator that must be sent to zero. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

7. Algebraic quantum gravity (AQG): III. Semiclassical perturbation theory.

Author

K Giesel and T Thiemann

Subjects
*QUANTUM gravity, *ASTRONOMICAL perturbation, *ABELIAN groups, *QUANTUM theory
Abstract

In the two previous papers of this series we defined a new combinatorial approach to quantum gravity, algebraic quantum gravity (AQG). We showed that AQG reproduces the correct infinitesimal dynamics in the semiclassical limit, provided one incorrectly substitutes the non-Abelian group SU(2) by the Abelian group U(1)3in the calculations. The mere reason why that substitution was performed at all is that in the non-Abelian case the volume operator, pivotal for the definition of the dynamics, is not diagonizable by analytical methods. This, in contrast to the Abelian case, so far prohibited semiclassical computations. In this paper, we show why this unjustified substitution nevertheless reproduces the correct physical result. Namely, we introduce for the first time semiclassical perturbation theory within AQG (and LQG) which allows us to compute expectation values of interesting operators such as the master constraint as a power series in with error control. That is, in particular, matrix elements of fractional powers of the volume operator can be computed with extremely high precision for sufficiently large power of in the expansion. With this new tool, the non-Abelian calculation, although technically more involved, is then exactly analogous to the Abelian calculation, thus justifying the Abelian analysis in retrospect. The results of this paper turn AQG into a calculational discipline. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

8. Algebraic quantum gravity (AQG): II. Semiclassical analysis.

Author

K Giesel and T Thiemann

Subjects
*QUANTUM gravity, *GENERAL relativity (Physics), *QUANTUM perturbations, *QUANTUM theory
Abstract

In the previous paper (Giesel and Thiemann 2006 Conceptual setup Preprintgr-qc/0607099) a new combinatorial and thus purely algebraical approach to quantum gravity, called algebraic quantum gravity (AQG), was introduced. In the framework of AQG, existing semiclassical tools can be applied to operators that encode the dynamics of AQG such as the master constraint operator. In this paper, we will analyse the semiclassical limit of the (extended) algebraic master constraint operator and show that it reproduces the correct infinitesimal generators of general relativity. Therefore, the question of whether general relativity is included in the semiclassical sector of the theory, which is still an open problem in LQG, can be significantly improved in the framework of AQG. For the calculations, we will substitute SU(2) with U(1)3. That this substitution is justified will be demonstrated in the third paper (Giesel and Thiemann 2006 Semiclassical perturbation theory Preprintgr-qc/0607101) of this series. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

9. ChemInform Abstract: Nucleophilic Organosilicon Intermediates Turned Electrophilic: (Trimethylsilyl)methyl, Trimethylsilyloxy and also 2-Tetrahydropyranyloxy as Terminators of Cycloadditions of Allyl Cations. A Short Route to Dehydrozizaenes (6-Methylenet

Author

U. Gibbels, H. M. R. Hoffmann, K. Giesel, J. Rabe, Ulrike Eggert, O. Koch, and R. Lies

Subjects
chemistry.chemical_compound, Trimethylsilyl, chemistry, Nucleophile, Electrophile, Organic chemistry, General Medicine, Organosilicon
Published
1988
Full Text
View/download PDF

11. Reduced loop quantization with four Klein–Gordon scalar fields as reference matter.

Author

K Giesel and A Vetter

Subjects
*HAMILTONIAN operator, *QUANTUM gravity, *MATTER, *PHASE space, *SCALAR field theory
Abstract

We perform a reduced phase space quantization of gravity using four Klein–Gordon scalar fields as reference matter as an alternative to the Brown–Kuchar dust model in Giesel and Thiemann (2010 Class. Quantum Grav. 27 175009), where dust scalar fields are used. We compare our results to an earlier model by Domagala et al (2010 Phys. Rev. D 82 104038) where only one Klein–Gordon scalar field is considered as reference matter for the Hamiltonian constraint but the spatial diffeomorphism constraints are quantized using Dirac quantization. As a result we find that the choice of four conventional Klein–Gordon scalar fields as reference matter leads to a reduced dynamical model that cannot be quantized using loop quantum gravity techniques. However, we further discuss a slight generalization of the action for the four Klein–Gordon scalar fields and show that this leads to a model which can be quantized in the framework of loop quantum gravity. By comparison of the physical Hamiltonian operators obtained from the model by Domagala et al (2010 Phys. Rev. D 82 104038) and the one introduced in this work we are able to make a first step towards comparing Dirac and reduced phase space quantization in the context of the spatial diffeomorphism constraints. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

12. Scalar material reference systems and loop quantum gravity.

Author

K Giesel and T Thiemann

Subjects
*QUANTUM gravity, *MATHEMATICAL invariants, *HAMILTONIAN systems, *QUANTUM theory, *GENERAL relativity (Physics)
Abstract

In the past, the possibility to employ (scalar) material reference systems in order to describe classical and quantum gravity directly in terms of gauge invariant (Dirac) observables has been emphasized frequently. This idea has been picked up more recently in loop quantum gravity with the aim to perform a reduced phase space quantization of the theory, thus possibly avoiding problems with the (Dirac) operator constraint quantization method for a constrained system. In this work, we review the models that have been studied on the classical and/or the quantum level and parametrize the space of theories considered so far. We then describe the quantum theory of a model that, to the best of our knowledge, has only been considered classically so far. This model could arguably be called the optimal one in this class of models considered as it displays the simplest possible true Hamiltonian, while at the same time reducing all constraints of general relativity. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results