93 results on '"Dipole excitation"'
Search Results
2. Dipole and quadrupole resonance excitation in linear quadrupoles.
- Author
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Konenkov NV
- Abstract
In the development of commercial quadrupole mass spectrometers, there is an interest in improving the performance characteristics such as transmission, resolution, and mass range. In particular, parametric and dipolar resonance excitation of trapping ions are used for linear quadrupole mass filters. Theoretical methods and numerical simulation of ion trajectories were applied for study of ion-optical properties. The review is devoted to description of different excitation methods to improve QMF performance and consists of three parts. The first part presents the results of a linear ion trap simulation for various operating conditions and excitation methods. The second part considers the effects of dipole excitation (DE) on the performance of the quadrupole mass filter. The last part analyzes the formation of stability islands by different methods of quadrupole excitation. To date conditions of mass separation in quadrupole mass filters with sin wave supply were described for stability islands of the first and third stability regions formed by quadrupole and DE. By complicating the electronics such methods allow to overcome the destructive influence of electric field distortions and obtain a resolving power and ion transmission efficiency comparable with commercial devices. At quadrupole resonance excitation by a two-frequency signal, it is possible to reduce the length of electrodes three times without losses in resolution and transmission, which reduces the cost of rod set production with micrometer accuracy. Dipole resonance excitation allows controlling the shape of the mass peak by changing amplitude and phase of the auxiliary AC signal. The main factors affecting the resolving power of a linear ion trap are described theoretically. The numerical modeling results are confirmed by experiment., Competing Interests: Declaration of conflicting interestsThe author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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3. Experimental Method and Data Analysis
- Author
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Manea, Vladimir and Manea, Vladimir
- Published
- 2015
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4. Paradigmatic Lessons from Nuclear Driplines
- Author
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Vaagen, J. S., Ershov, S. N., Zhukov, M. V., and Greiner, Walter, Editor-in-chief
- Published
- 2015
- Full Text
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5. Electromagnetics of Metals and Theory Fundamentals
- Author
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Long, Yi-Tao, Jing, Chao, Long, Yi-Tao, and Jing, Chao
- Published
- 2014
- Full Text
- View/download PDF
6. Super-Resolution Scanning Near-Field Optical Microscopy
- Author
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Fischer, Ulrich C., Heimel, Jörg, Maas, Hans-Jürgen, Fuchs, Harald, Weeber, Jean Claude, Dereux, Alain, Tominaga, Junji, editor, and Tsai, Din P., editor
- Published
- 2003
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7. Two Phonon Excitations in Heavy Nuclei Studied in Photon Scattering Experiments
- Author
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von Brentano, P., Zilges, A., Herzberg, R.-D., Kneissl, U., Pitz, H. H., Scheid, Werner, editor, and Sandulescu, Aurel, editor
- Published
- 1994
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8. Low Lying Electric Dipole Excitations and the Interacting Boson Model
- Author
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von Brentano, P., Zilges, A., Zamfir, N. V., Herzberg, R. -D., Gruber, Bruno, editor, and Otsuka, Takaharu, editor
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- 1993
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9. Spectroscopy of Quantum-Dot Atoms
- Author
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Heitmann, Detlef, Meurer, B., Demel, T., Grambow, P., Ploog, K., Rosencher, Emmanuel, editor, Vinter, Børge, editor, and Levine, Barry, editor
- Published
- 1992
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10. Dipole excitations of closed-shell alkali-metal clusters
- Author
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Guet, C., Johnson, W. R., Araki, H., editor, Brézin, E., editor, Ehlers, J., editor, Frisch, U., editor, Hepp, K., editor, Jaffe, R. L., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglböck, W., editor, Schmidt, Rüdiger, editor, Lutz, Hans O., editor, and Dreizler, Reiner, editor
- Published
- 1992
- Full Text
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11. Dipole excitation of Li6 and Be9 studied with an extended quantum molecular dynamics model
- Author
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Bo-Song Huang and Yu-Gang Ma
- Subjects
Physics ,Dipole ,Mean field theory ,Deuterium ,Atomic physics ,Quantum molecular dynamics ,Resonance (particle physics) ,Spectral line ,Dipole excitation ,Lower energy - Abstract
The $\ensuremath{\alpha}$ ($^{4}\mathrm{He}$)-clustering structure is a common phenomenon in light nuclei due to the decreasing contribution of the mean field in few-body systems. In this work, we presented calculations of giant dipole resonance (GDR) excitations for two non-$\ensuremath{\alpha}$-conjugate light nuclei, namely $^{6}\mathrm{Li}$ and $^{9}\mathrm{Be}$, within a framework of an extended quantum molecular dynamics model. For $^{6}\mathrm{Li}$, we investigated the GDR spectra from the two-body clustering structure with $\ensuremath{\alpha}\phantom{\rule{4pt}{0ex}}+$ deuteron as well as the three-body structure with $\ensuremath{\alpha}+n+p$, and found that the major $\ensuremath{\alpha}$-clustering contribution on the GDR peak is located at around 31 MeV, while the resonance contributions between clusters, namely $\ensuremath{\alpha}$ and deuteron or $(n+p)$, are located on the lower energy side, which can be regarded as the pygmy dipole resonance (PDR). For $^{9}\mathrm{Be}$, a mixture configuration contribution for the chain-like structure and Borromean-like structure of the $\ensuremath{\alpha}\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}n\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}\ensuremath{\alpha}$ configuration can explain its GDR results.
- Published
- 2021
12. Low-energy dipole excitation mode in O18 with antisymmetrized molecular dynamics
- Author
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Yuki Shikata and Yoshiko Kanada-En'yo
- Subjects
Physics ,010308 nuclear & particles physics ,Generator (category theory) ,State (functional analysis) ,01 natural sciences ,Dipole excitation ,Projection (relational algebra) ,Molecular dynamics ,Dipole ,Low energy ,0103 physical sciences ,Atomic physics ,010306 general physics ,Nuclear theory - Abstract
Low-energy dipole (LED) excitations in $^{18}\mathrm{O}$ were investigated using a combination of the variation after $K$ projection in the framework of antisymmetrized molecular dynamics with $\ensuremath{\beta}$ constraint with the generator coordinate method. We obtained two LED states, namely, the ${1}_{1}^{\ensuremath{-}}$ state with a dominant shell-model structure and the ${1}_{2}^{\ensuremath{-}}$ state with a large $^{14}\mathrm{C}+\ensuremath{\alpha}$ cluster component. Both these states had significant toroidal dipole (TD) and compressive dipole (CD) strengths, indicating that the TD and CD modes are not separated but mixed in the LED excitations of $^{18}\mathrm{O}$. This is unlike the CD and TD modes for well-deformed nuclei such as $^{10}\mathrm{Be}$, where the CD and TD modes are generated as ${K}^{\ensuremath{\pi}}={0}^{\ensuremath{-}}$ and ${K}^{\ensuremath{\pi}}={1}^{\ensuremath{-}}$ excitations, respectively, in a largely deformed state.
- Published
- 2021
13. Study of Collective Dipole Excitations below the Giant Dipole Resonance at HIγS.
- Author
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Tonchev, A. P., Angell, C., Boswell, M., Chyzh, A., Howell, C. R., Karwowski, H. J., Kelley, J. H., Tornow, W., Tsoneva, N., and Wu, Y. K.
- Subjects
- *
DIPOLE moments , *PARTICLES (Nuclear physics) , *RADIOACTIVITY , *GAMMA rays , *IONIZING radiation , *NUCLEAR reactions - Abstract
The High-Intensity Gamma-ray Source utilizing intra-cavity back-scattering of free electron laser photons from relativistic electrons allows one to produce a unique beam of high-flux gamma rays with 100% polarization and selectable energy and energy resolution which is ideal for low-energy γ-ray scattering experiments. Nuclear resonance fluorescence experiments have been performed on N=82 nuclei. High sensitivity studies of E1 and M1 excitations at energies close to the neutron emission threshold have been performed. The method allows the determination of excitation energies, spin, parities, and decay branching ratios of the pygmy dipole mode of excitation. The observations are compared with calculations using statistical and quasi-particle random-phase approximations. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
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14. Dipole Excitation of Periodic Metallic Structures.
- Author
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Lovat, G, Araneo, R, and Celozzi, S
- Subjects
- *
MAGNETIC dipoles , *LEAKY-wave antennas , *NEAR field communication , *ELECTROMAGNETIC shielding , *MAGNETIC pole - Abstract
The excitation of a periodic structure composed of two- or three-dimensional metallic scatterers by a finite dipole source is studied through the application of the Array Scanning Method. The difficulties in the numerical implementation are discussed in details, providing general guidelines and suggesting a useful preprocessing procedure to determine the number of quadrature points needed in the involved spectral integrations to obtain a given accuracy in the field calculation. The problem of transmission and reflection from two typical periodic screens (arrays of apertures in a metallic plate and arrays of metallic spheres) is first addressed in order to show the differences between a finite-source and the conventional plane-wave excitation. Finally, results for the near field of a recently proposed two-dimensional periodic leaky-wave antenna (an array of metallic patches over a ground plane) are also presented examining for the first time its main characteristics. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
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15. SUM RULE FOR A SCHIFF-LIKE DIPOLE MOMENT.
- Author
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RADUTA, A. A. and BUDACA, R.
- Subjects
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SUM rules (Physics) , *DIPOLE moments , *FORCE & energy , *OPERATOR theory , *APPROXIMATION theory , *MICROCLUSTERS , *ELECTRONIC excitation - Abstract
The energy-weighted sum rule for an electric dipole transition operator of a Schiff type differs from the Thomas-Reiche-Kuhn (TRK) sum rule by several corrective terms which depend on the number of system components, ${\cal N}$. For illustration the formalism was applied to the case of Na clusters. One concludes that the random phase approximation (RPA) results for Na clusters obey the modified TRK sum rule. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
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16. LOW-FREQUENCY DIPOLAR EXCITATION OF A PERFECT ELLIPSOIDAL CONDUCTOR.
- Author
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PERRUSSON, GAËLE, VAFEAS, PANAYIOTIS, and LESSELIER, DOMINIQUE
- Subjects
ELECTRONIC excitation ,ELLIPSOIDS ,HARMONIC functions ,ELECTRICAL harmonics ,ELECTRICAL conductors - Abstract
This paper deals with the scattering by a perfectly conductive ellipsoid under magnetic dipolar excitation at low frequency. The source and the ellipsoid are embedded in an infinite homogeneous conducting ground. The main idea is to obtain an analytical solution of this scattering problem in order to have a fast numerical estimation of the scattered field that can be useful for real data inversion. Maxwell equations and boundary conditions, describing the problem, are firstly expanded using low-frequency expansion of the fields up to order three. It will be shown that fields have to be found incrementally. The static one (term of order zero) satisfies the Laplace equation. The next non-zero term (term of order two) is more complicated and satisfies the Poisson equation. The order-three term is independent of the previous ones and is described by the Laplace equation. They constitute three different scattering problems that are solved using the separated variables method in the ellipsoidal coordinate system. Solutions are written as expansions on the few analytically known scalar ellipsoidal harmonics. Details axe given to explain how those solutions are achieved with an example of numerical results. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
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17. DINEUTRON CORRELATION IN THE GROUND STATE AND E1 EXCITATIONS OF BORROMEAN NUCLEI.
- Author
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HAGINO, K., SAGAWA, H., and OISHI, T.
- Subjects
- *
PAIRING correlations (Nuclear physics) , *PARTICLES (Nuclear physics) , *NUCLEAR physics , *NEUTRONS , *NUCLEAR excitation - Abstract
Using a three-body model with density-dependent contact interaction, we discuss the role of dineutron correlation in the ground state properties as well as in the dipole excitation of typical weakly-bound Borromean nuclei, 11Li and 6He. We show that, while both the nuclei manifest themselves similar strong dineutron correlations to each other in the ground state, the energy distributions for the two emitted neutrons from the dipole excitation are considerably different. We also discuss briefly the diproton correlation in a proton-rich Borromean nucleus, 17Ne. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
18. Dipole excitations of Ar substrate in contact with Na clusters
- Author
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Dinh, P.M., Reinhard, P.-G., and Suraud, E.
- Subjects
- *
ELECTRONIC excitation , *SURFACE chemistry , *ARGON , *METAL clusters , *STEREOCHEMISTRY , *MOLECULAR dynamics , *SODIUM - Abstract
Abstract: We analyze the excitation of Ar substrate in contact with Na clusters using a previously developed hierarchical model for the description of the system constituted of a highly reactive metal cluster in contact with a rather inert substrate. Particular attention is paid to the dipole excitation of the Ar atoms and the energy stored therein. The Na clusters are considered at different charge states, anions, cations, and neutral clusters for the case of deposition and a highly ionized cluster embedded in a matrix. It is found that the dipole polarization of the Ar atoms stores the largest fraction of energy in the case of charged clusters. Some, although smaller, polarization is also observed for polar clusters, as Na6. The effect is predominantly induced by the electrostatic interaction. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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19. Anapole arising from a Mie scatterer with dipole excitation
- Author
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Jorge R. Zurita-Sánchez
- Subjects
Physics ,Dipole ,Metallic particle ,High-refractive-index polymer ,Physics::Optics ,Physics::Atomic Physics ,Dielectric ,Atomic physics ,Computer Science::Databases ,Dipole excitation - Abstract
This paper shows that a dipole close to a subwavelength sphere can give rise to an anapole, namely the dipole-scatterer is a non-radiating system. This state can be achieved with either a dielectric (high refractive index) or metallic particle.
- Published
- 2019
20. Low-energy dipole excitation modes in ${}^{10}$Be
- Author
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Hiroyuki Morita, Yuki Shikata, and Yoshiko Kanada-En'yo
- Subjects
Physics ,Toroid ,Nuclear Theory ,Generator (category theory) ,General Physics and Astronomy ,FOS: Physical sciences ,State (functional analysis) ,Dipole excitation ,Nuclear Theory (nucl-th) ,Dipole ,Low energy ,Cluster (physics) ,Physics::Atomic Physics ,Atomic physics ,Nuclear theory - Abstract
Low-energy dipole excitations in ${}^{10}$Be were investigated based on the generator coordinate method with $\alpha + {}^6$He and $\alpha + \alpha + 2n$ cluster models. We obtained three $1^-$ states in $E_{x} < 15$~MeV, which show different characters in the $E1$, compressive dipole, and toroidal dipole transition strengths. We found the strong toroidal dipole transition in the $1_1^-$ state, remarkable $E1$ strength in the $1^-_2$ state, and the strong $E1$ and compressive dipole strength in the $1^-_3$ state. The $1^-_1$ is described by the $\alpha + {}^6$He cluster structure, where as the $1^-_2$ and $1^-_3$ states are understood by three-body excitations of the $\alpha + \alpha + 2n$ clustering., Comment: 20 pages, 8 figures
- Published
- 2019
- Full Text
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21. Beyond dipole excitation: the performance of quadrupole-based Huygens’ metasurface
- Author
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Han Ye, Li Yu, Yu Wang, Yumin Liu, Zhongyuan Yu, Yuhang Sun, and Chang Liu
- Subjects
Diffraction ,Physics ,business.industry ,Mie scattering ,Physics::Optics ,Resonance ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Dipole excitation ,Computational physics ,010309 optics ,Dipole ,Optics ,Excited state ,0103 physical sciences ,Quadrupole ,0210 nano-technology ,business ,Refractive index - Abstract
Due to the utilization of overlapped dipole resonances, traditional Huygens’ metasurfaces suffer from dipole interactions. In this Letter, we propose a design of phase-gradient Huygens’ metasurface based on the quadrupole resonances excited in the cross-shaped structures. The quadrupole resonances are theoretically shown insensitive to the quadrupole interactions. Benefiting from this intrinsic property, the proposed metasurface can well suppress element interaction influence and exhibits some impressive properties, including the ability to suppress high diffraction orders, tunable anomalous refractive angles, and high transmission efficiency. The numerical results show promising potential for quadrupole resonances to be applied in advanced Huygens’ metasurface designs.
- Published
- 2020
22. Three-body vs. dineutron approach to two-neutron radiative capture in 6He
- Author
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L. V. Grigorenko, N. B. Shulgina, and Mikhail V. Zhukov
- Subjects
Physics ,Nuclear and High Energy Physics ,Nuclear Theory ,Basis (linear algebra) ,010308 nuclear & particles physics ,Strength function ,Radiative capture ,Three-body hyperspherical harmonics method ,Extrapolation ,Neutron halo ,FOS: Physical sciences ,01 natural sciences ,lcsh:QC1-999 ,Dipole excitation ,Two-neutron nonresonant radiative capture reaction ,Nuclear Theory (nucl-th) ,Dynamical dineutron model ,0103 physical sciences ,Soft dipole mode ,Neutron ,Atomic physics ,010306 general physics ,Nuclear theory ,lcsh:Physics - Abstract
The low-energy behavior of the strength function for the $1^-$ soft dipole excitation in $^{6}$He is studied theoretically. Use of very large basis sizes and well-grounded extrapolation procedures allows to move to energies as small as 1 keV, at which the low-energy asymptotic behavior of the E1 strength function seems to be achieved. It is found that the low-energy behavior of the strength function is well described in the effective three-body "dynamical dineutron model". The astrophysical rate for the $\alpha$+$n$+$n \rightarrow ^6$He+$\gamma$ is calculated. Comparison with the previous calculations is performed., Comment: 6 pages, 9 figures
- Published
- 2020
23. The Double-Excitation of the Li 1s(2s2p 1P)2P Term by Proton Impact
- Author
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Ziem, P., Schilling, R., Burke, P. G., editor, Kleinpoppen, H., editor, Fabian, Derek J., editor, Kleinpoppen, Hans, editor, and Watson, Lewis M., editor
- Published
- 1981
- Full Text
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24. Giant resonances in muon capture
- Author
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Cannata, Francesco, Überall, Herbert, Cannata, Francesco, and Überall, Herbert
- Published
- 1980
- Full Text
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25. Meson Theoretical Models of Three-Nucleon Forces
- Author
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Coon, Sidney A., Mitter, H., editor, Plessas, W., editor, Ciofi degli Atti, Claudio, editor, Benhar, Omar, editor, Pace, Emanuele, editor, and Salmè, Giovanni, editor
- Published
- 1986
- Full Text
- View/download PDF
26. Computing Techniques for Electrostatic Perturbations
- Author
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Jones, W. D., Doucet, H. J., Buzzi, J. M., Jones, W. D., Doucet, H. J., and Buzzi, J. M.
- Published
- 1985
- Full Text
- View/download PDF
27. A Comparison of the Reflection -Absorption Infrared Method with the Electron Energy Loss Method for Studying Vibrations at Surfaces
- Author
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Greenler, Robert G., Caudano, R., editor, Gilles, J.-M., editor, and Lucas, A. A., editor
- Published
- 1982
- Full Text
- View/download PDF
28. EELS of Collective Surface Modes
- Author
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Andersson, Stig, Caudano, R., editor, Gilles, J.-M., editor, and Lucas, A. A., editor
- Published
- 1982
- Full Text
- View/download PDF
29. TENSOR EFFECTS IN PYGMY DIPOLE EXCITATION
- Author
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Kutsal Bozkurt and Esra Yüksel
- Subjects
Coupling constant ,Physics ,Nuclear and High Energy Physics ,Dipole ,Quantum electrodynamics ,Nuclear Theory ,Quasiparticle ,General Physics and Astronomy ,Tensor ,Nuclear Experiment ,Random phase approximation ,Dipole excitation - Abstract
We investigate tensor effects in pygmy dipole excitations for the case of neutron-rich nuclei 68 Ni and 124 Sn using effective nucleon–nucleon Skyrme interaction. We use the Hartree–Fock–Bogoliubov (HFB) theory and employ the quasiparticle random phase approximation (QRPA). We calculate and compare the PDR and also GDR strength in the PDR–GDR energy region for QRPA calculations with and without tensor correlations. The most obvious results for the dipole excitations calculations are strongly dependent on the tensor terms. We see that the tensor correlations are more active at around 14–20 MeV , especially for the neutron-rich nuclei 68 Ni . We also compare the PDR calculations with their experimental results for the different proton–neutron tensor coupling constants.
- Published
- 2011
30. ISOVECTOR PYGMY DIPOLE EXCITATION IN NEUTRON-RICH NUCLEI
- Author
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Kutsal Bozkurt
- Subjects
Physics ,Nuclear and High Energy Physics ,Isovector ,General Physics and Astronomy ,Astronomy and Astrophysics ,Resonance (particle physics) ,Dipole excitation ,Nuclear physics ,Dipole ,Density dependent ,Quasiparticle ,Neutron ,Atomic physics ,Random phase approximation - Abstract
We investigate isovector pygmy dipole resonance (IVPDR) for the case of neutron-rich nuclei 68 Ni , 130 Sn and 134 Sn using effective nucleon–nucleon Skyrme interaction. We use the Hartree–Fock–Bogoliubov (HFB) theory and employ the (quasiparticle) random phase approximation (Q)RPA. We calculate and compare the PDR strength in the PDR energy region for the case of density dependent central and full interaction modes for RPA and QRPA calculations. We observe that the results for the pygmy dipole resonance for neutron-rich soft nuclei 68 Ni that we consider are in reasonable agreement with their experimental results in both interactions and calculations. We also study the PDR for highly neutron-rich heavy nuclei, such as 130 Sn and 134 Sn . We see that only the QRPA calculation with full interaction is in good agreement with the experimental results for these nuclei and with a recent study in the literature. We find that the PDR strength distribution sensitively depends on the chosen interaction modes, especially for the neutron-rich heavy nuclei 134 Sn .
- Published
- 2010
31. DINEUTRON CORRELATION IN THE GROUND STATE AND E1 EXCITATIONS OF BORROMEAN NUCLEI
- Author
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Tomohiro Oishi, Kouichi Hagino, and Hiroyuki Sagawa
- Subjects
Physics ,Nuclear and High Energy Physics ,Borromean nucleus ,General Physics and Astronomy ,Astronomy and Astrophysics ,Neutron ,Atomic physics ,Ground state ,Dipole excitation - Abstract
Using a three-body model with density-dependent contact interaction, we discuss the role of dineutron correlation in the ground state properties as well as in the dipole excitation of typical weakly-bound Borromean nuclei, 11 Li and 6 He . We show that, while both the nuclei manifest themselves similar strong dineutron correlations to each other in the ground state, the energy distributions for the two emitted neutrons from the dipole excitation are considerably different. We also discuss briefly the diproton correlation in a proton-rich Borromean nucleus, 17 Ne .
- Published
- 2010
32. Mesoscopic physics of a one-dimensional Bose gas : persistent currents and collective dipole excitations
- Author
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Cominotti, Marco, Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes, Anna Minguzzi, and Frank W. J. Hekking
- Subjects
Une dimension ,Excitations dipolaires ,One-Dimension ,Mesoscopic physics ,Courants persistants ,Bose gaz ,Quantum gases ,Gaz quantiques ,Persistent currents ,Dipole excitation ,Physique mésoscopique ,Bose gas ,[PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] - Abstract
Thanks to the experimental breakthrough of the last years in the manipulation of ultra cold atomic gases, it has become possible to realize low-dimensional and mesoscopic quantum fluids. The object of this thesis is the theoretical investigation of a few mesoscopic systems that can be realized with a one-dimensional Bose gas. These systems exhibit interesting quantum phenomena, and are potentially relevant for technological applications. We study the phenomenon of persistent currents induced by stirring the gas confined on a ring with a potential barrier, we examine the feasibility of a qubit based on the superposition of current states in a ring lattice threaded by a gauge field in the presence of a weak-link, and we investigate the dipole excitation of the gas in a split trap induced by an out-of-equilibrium displacement of the external potential. In all these cases, we apply a combination of analytical and numerical approaches that allow to cover all the interaction regimes. As a recurring theme, we disclose a so-far unknown regime of maximal screening of the barrier potential by the fluid, arising from the interplay of effects due to interactions and quantum fluctuations. These results have significant consequences for the behaviour of such systems and are important for the ongoing and future realization of ultracold atomic gases devices.; Ces dernières années d'importantes avancées techniques dans la manipulation des gaz atomiques ultrafroids ont ouvert la voie à la réalisation de fluides quantiques mésoscopiques de basse dimension. L'objet de cette thèse est l'étude théorique de certains systèmes mésoscopiques réalisables avec un gaz de Bose unidimensionel. Ces systèmes présentent des phénomènes quantiques intéressants, et sont potentiellement utiles en vue d'applications technologiques. Nous étudions le phénomène des courants permanents induits dans un gaz confiné sur un anneau par la rotation d'une barrière de potentiel, nous examinons la faisabilité d'un qubit fondé sur la superposition d'états de courant dans un réseau en forme d'anneau traversé par un champ de jauge et contenant un 'weak-link', ainsi que l'excitation dipolaire du gaz dans un 'split-trap' induit par le déplacement hors équilibre du potentiel externe. Dans tous ces cas, nous combinons diverses approches analytiques et numériques, qui permettent de couvrir l'ensemble des régimes d'interactions. Nous mettons en lumière un régime jusque-là inconnu, d'écrantage maximal des barrières de potentiel par le fluide, dû à une competition entre les effets des interactions et des fluctuations quantiques. Ces résultats ont des conséquences significatives sur le comportement de tels systèmes et, de ce fait, sont importants pour les réalisations en cours et à venir de dispositifs à gaz d'atomes ultrafroids.
- Published
- 2015
33. Long-range dynamic polarization potentials forBe11projectiles onZn64
- Author
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W. Y. So, Ki-Seok Choi, Kyungsik Kim, and Myung-Ki Cheoun
- Subjects
Physics ,Elastic scattering ,Nuclear and High Energy Physics ,Projectile ,Excited state ,Coulomb ,Absorption effect ,Inelastic scattering ,Atomic physics ,Polarization (waves) ,Dipole excitation - Abstract
We investigate the effects of the long-range dynamic polarization (LRDP) potential, which consists of the Coulomb dipole excitation (CDE) potential and the long-range nuclear (LRN) potential, for the $^{11}\mathrm{Be}$ projectile on $^{64}\mathrm{Zn}$. To study these effects, we perform a ${\ensuremath{\chi}}^{2}$ analysis of an optical model including the LRDP potential as well as a conventional short-range nuclear (SRN) potential. To take these effects into account, we argue that both the CDE and LRN potentials are essential to explaining the experimental values of ${P}_{E}$, which is the ratio of the elastic scattering cross section to the Rutherford cross section. The Coulomb and nuclear parts of the LRDP potential are found to contribute to a strong absorption effect. Strong absorption occurs because the real part of the CDE and LRN potentials lowers the barrier, and the imaginary part of the CDE and LRN potentials removes the flux from the elastic channel in the $^{11}\mathrm{Be}+^{64}\mathrm{Zn}$ system. Finally, we extract the total reaction cross section ${\ensuremath{\sigma}}_{R}$ including the inelastic, breakup, and fusion cross sections. The contribution of the inelastic scattering by the first excited state at ${\ensuremath{\varepsilon}}_{\mathrm{x}}^{1\mathrm{st}}=0.32\phantom{\rule{4pt}{0ex}}\mathrm{MeV}\phantom{\rule{4pt}{0ex}}(1/{2}^{\ensuremath{-}})$ is found to be relatively large and cannot be ignored. In addition, our results are shown to agree quite well with the experimental breakup reaction cross section by using a fairly large radius parameter.
- Published
- 2015
34. Experimental Method and Data Analysis
- Author
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Vladimir Manea
- Subjects
Physics ,Range (particle radiation) ,Finite volume method ,Cyclotron ,chemistry.chemical_element ,Space (mathematics) ,Dipole excitation ,Computational physics ,law.invention ,Magnetic field ,chemistry ,law ,Subatomic particle ,Helium - Abstract
Generally speaking, charged-particle traps are devices which achieve the confinement of charged subatomic, atomic or molecular particles in a finite volume of space, through a combination of electric and magnetic fields (which can be static or dynamic) [Maj05]. Due to their wide range of applications, charged-particle traps have become key components of experimental-physics facilities today [Wer09].
- Published
- 2015
35. Long-range dynamic polarization potentials forLi11+Pb208andHe6+Pb208systems
- Author
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Ki-Seok Choi, W. Y. So, Myung-Ki Cheoun, and Kyungsik Kim
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Coulomb ,Surface type ,Halo ,Atomic physics ,Polarization (waves) ,Dipole excitation - Abstract
We investigate the effects of long-range dynamic polarization on elastic cross sections for heavy-ion collisions which comprise the Coulomb dipole excitation (CDE) potential and the long-range nuclear (LRN) potential. To study these effects, we perform a ${\ensuremath{\chi}}^{2}$ analysis for the elastic cross sections of $^{11}\mathrm{Li}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}^{208}\mathrm{Pb}$ and $^{6}\mathrm{He}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}^{208}\mathrm{Pb}$ systems using the long-range dynamic polarization potentials. For the CDE we formulate some empirical models to reproduce the experimental Coulomb dipole strength $B(E1)$ distribution and apply to the collision of $^{11}\mathrm{Li}$ and $^{6}\mathrm{He}$. But the CDE potential turns out to be not enough to explain the experimental data relevant to the nuclei. It leads us to additionally take the LRN potential peculiar to these halo nuclei into account. Our model, which was constructed by adding the CDE and LRN potentials to the conventional short-range nuclear potential corrected by the Coulomb interaction, provides a good description of the experimental data. In particular, the surface type is shown to be more reasonable rather than the volume type in the LRN potential.
- Published
- 2014
36. Paradigmatic Lessons from Nuclear Driplines
- Author
-
Mikhail V. Zhukov, J. S. Vaagen, and S. N. Ershov
- Subjects
Theoretical physics ,Engineering ,business.industry ,Degrees of freedom ,Halo nucleus ,business ,Nuclear matter ,Parallels ,Dipole excitation ,Nuclear architecture ,Duality (electricity and magnetism) ,Epistemology - Abstract
Science is—as emphasized 50 years ago by Thomas Kuhn in his academic bestseller The Structure of Scientific Revolutions—driven by paradigms, rooted in outstanding discoveries and practice. At the centennial for the nuclear atom, it may be appropriate to address the current paradigmatic situation for nuclear physics on background of the large investments made during the last decades. Following Rutherford’s paradigm, nuclear physics has developed by colliding nuclei and from studying the fragments that emerge. With restriction to new forms of transient cold nuclear matter, we will address if and how new discoveries have influenced the way we think about nuclear architecture, drawing parallels with comparable development in other branches of science. Recent discoveries in halo nuclei, \(^{11}\)Be and the Borromean \(^{22}\)C will serve as our cardinal examples. The challenges at driplines may appear less dramatic than what calls for a Kuhnian turnover, still we hope to convey that valuable lessons may be learned. The attention-grabbing dripline lessons we address are rooted in emergent degrees of freedom involving cluster constituents. This is a great challenge for the ruling paradigm, a shell-model inspired ab initio nucleon-based theory, developed and tested for stable nuclei, and currently being tuned to encompass dripline lessons. Our mental pictures and dynamic understanding of many of the outstanding dripline phenomena will, however, remain linked to cluster degrees of freedom. This duality makes our paradigmatic lessons conceptually less dramatic than what Kuhn’s “incommensurability” may imply.
- Published
- 2014
37. Effect of long range potentials on the elastic cross section for theLi11+Pb208system
- Author
-
W. Y. So, Kyungsik Kim, and Myung-Ki Cheoun
- Subjects
Physics ,Elastic scattering ,Nuclear and High Energy Physics ,Cross section (physics) ,Range (particle radiation) ,Dipole ,Forward angle ,Coulomb ,Atomic physics ,Electric dipole transition ,Dipole excitation - Abstract
For the $^{11}\mathrm{Li}+^{208}\mathrm{Pb}$ system, we find that the breakup process takes place from the forward angle or far distance region through the interaction distance which is obtained from ratios of elastic scattering cross sections to the Rutherford cross section. It is well known that the behavior of the $^{11}\mathrm{Li}+^{208}\mathrm{Pb}$ system is closely related to Coulomb dipole excitation effect. From the first ${\ensuremath{\chi}}^{2}$ analysis for the elastic cross section of the $^{9}\mathrm{Li}+^{208}\mathrm{Pb}$ system, we obtain the short-range potential of the $^{11}\mathrm{Li}+^{208}\mathrm{Pb}$ system by exploiting the optical model calculation for the Coulomb dipole excitation effect. To include the effect of the long-range interaction, we use a dynamic complex polarization potential including the Coulomb dipole potential and a long-range nuclear potential with Woods-Saxon form. Using the second ${\ensuremath{\chi}}^{2}$ analysis for the elastic cross section of the $^{11}\mathrm{Li}+^{208}\mathrm{Pb}$ system, we obtain the electric dipole transition probabilities $B(E1)$ which becomes 1.42 ${e}^{2}{\mathrm{fm}}^{2}$ and 1.41 ${e}^{2}{\mathrm{fm}}^{2}$ at ${E}_{\mathrm{c}.\mathrm{m}.}$ = 23.1 MeV and 28.3 MeV, respectively.
- Published
- 2014
38. Gamma deexcitation of the 180m Ta isomer
- Author
-
N. Yu. Shirikova, V.G. Soloviev, and A. V. Sushkov
- Subjects
Physics ,Nuclear and High Energy Physics ,Elementary particle ,State (functional analysis) ,Atomic and Molecular Physics, and Optics ,Dipole excitation ,Dipole ,Energy interval ,Physics::Atomic and Molecular Clusters ,Physics::Chemical Physics ,Atomic physics ,Nuclear Experiment ,Ground state ,Excitation - Abstract
Vibrational states built on the K π = 9− isomer and on the ground state (K π = 1+) in 180Ta are calculated within the quasiparticle-phonon nuclear model using the 178Hf nucleus as a core. A procedure for calculating the rates of K-allowed γ-ray transitions from vibrational states built on the isomer to those built on the ground state is presented. The probabilities of two-step processes consisting of a dipole excitation of the isomer and successive E1 and E2 transitions from them to vibrational states built on the ground state of the 180Ta nucleus are calculated. Two-step transitions from the isomer to vibrational states below 2.7 MeV and to the vibrational states built on the ground state appear to be very weak. There are many E1 transitions from the vibrational states built on the isomer to the vibrational states built on the ground state. They are weak and cannot be responsible for the strong deexcitation of 180m Ta in the relevant (γ, γ′) reaction. A decisive role is played by collective E2 transitions from dipole excitations in several excitation energy intervals ranging between 2.7 and 4.0 MeV. These highly intense K-allowed two-step γ-ray transitions can be responsible for the strong deexcitation of the 180m Ta state in the (γ, γ′) reactions.
- Published
- 2001
39. Positronium and Polyelectrons
- Author
-
Andrzej Czarnecki
- Subjects
Physics ,Nuclear and High Energy Physics ,Physics::Atomic and Molecular Clusters ,Molecule ,Physics::Atomic Physics ,Physics::Chemical Physics ,Atomic physics ,Hyperfine structure ,Dipole excitation ,Ion ,Positronium - Abstract
Properties of positronium (Ps), its negative ion, and the recently discovered positronium molecule are briefly reviewed. Emphasis is on the recent progress and on quantities of current experimental interest, including the Ps atomic and molecular spectrum, and the ion lifetime.
- Published
- 2009
40. Electron–hole pair creation at simple metal surfaces
- Author
-
Ulf Jonasson, S. Andersson, and Martin Sjöstrand
- Subjects
SIMPLE (dark matter experiment) ,Electron energy loss spectroscopy ,chemistry.chemical_element ,Surfaces and Interfaces ,Electron hole ,Electron ,Condensed Matter Physics ,Dipole excitation ,Surfaces, Coatings and Films ,Metal ,Low energy ,chemistry ,Aluminium ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Atomic physics - Abstract
Cross-sections for dipole excitation of low energy (0.1–0.3 eV) electron–hole pairs at the (111) and (100) surfaces of aluminium have been measured with use of electron energy loss spectroscopy. We observe a substantial crystal-face effect at low incident electron energies (
- Published
- 1998
41. Unresolved dipole strength in spectra of the157Gd(γ,γ′)reaction
- Author
-
P. von Neumann-Cosel, H. H. Pitz, Joachim Enders, Achim Richter, U. Kneissl, and N. Huxel
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Atomic physics ,Energy (signal processing) ,Lower limit ,Spectral line ,Excitation ,Dipole excitation ,Photon scattering - Abstract
A recently proposed fluctuation analysis of resonant photon scattering spectra [J. Enders et al., Phys. Rev. Lett. 79, 2010 (1997)] is applied to the ${}^{157}\mathrm{Gd}(\ensuremath{\gamma},{\ensuremath{\gamma}}^{\ensuremath{'}})$ reaction. Evidence for unresolved strength in the experimental background is found which amounts to a total dipole excitation strength of $\ensuremath{\sum}g{\ensuremath{\Gamma}}_{0}^{\mathrm{red}}{=(30}_{\ensuremath{-}10}^{+6}){\mathrm{m}\mathrm{e}\mathrm{V}/\mathrm{M}\mathrm{e}\mathrm{V}}^{3}$ in the excitation energy range 2.5--4 MeV. Assuming a smooth variation of the $M1/E1$ strength ratio in the neighboring even-mass nuclei, the $M1$ part can be estimated to be ${B(M1)=(2.0}_{\ensuremath{-}0.7}^{+0.4})$ ${\ensuremath{\mu}}_{N}^{2}.$ This value is close to the expectation of sum rules. We discuss possible sources of errors which suggests that the obtained value represents a lower limit only.
- Published
- 1998
42. Observation of the1+scissors mode in theγ-soft nucleusBa134
- Author
-
H. H. Pitz, J. Margraf, H. Maser, Norbert Pietralla, Andreas Zilges, U. Kneissl, R.-D. Herzberg, and P. von Brentano
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Photon ,medicine.anatomical_structure ,Phonon ,medicine ,Sum rule in quantum mechanics ,Atomic physics ,Nucleus ,Dipole excitation ,Energy (signal processing) ,Excitation - Abstract
A photon scattering experiment was performed on the $\ensuremath{\gamma}$-soft nucleus $^{134}\mathrm{Ba}$ with photon energies of ${E}_{\ensuremath{\gamma}}l4.1$. Around 3 MeV excitation energy a fragmented ${1}^{+}$ scissors mode as well as the ${({2}^{+}\ensuremath{\bigotimes}{3}^{\ensuremath{-}})}_{{1}^{\ensuremath{-}}}$ two-phonon dipole state were identified. The dipole excitation strengths were measured. The excitation strength of the scissors mode in this $\ensuremath{\gamma}$-soft nucleus is well reproduced by an empirical $M1$ sum rule that generalizes the "${\ensuremath{\delta}}^{2}$ law" to nuclei without axial symmetry. The IBM-2 describes the mixed-symmetry states in $^{134}\mathrm{Ba}$ and their decay pattern. A large $\frac{E2}{M1}$ mixing ratio for the ${1}^{+}$\ensuremath{\rightarrow}${2}_{1}^{+}$ decay of the scissors mode to the ${2}_{1}^{+}$ state is predicted by the IBM-2. The new result from $^{134}\mathrm{Ba}$ together with a similar previous observation in $^{196}\mathrm{Pt}$ corroborates the scissors mode as a typical excitation mode of $\ensuremath{\gamma}$-soft nuclei.
- Published
- 1996
43. Direct proof of the two-phonon character of the dipole excitations inNd142andSm144around 3.5 MeV
- Author
-
Andreas Zilges, P. von Brentano, Manfred Wilhelm, and E. Radermacher
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Phonon ,Proton scattering ,Nuclear Theory ,Gamma ray ,Direct proof ,Atomic physics ,Inelastic scattering ,Dipole excitation ,Excitation - Abstract
Resonant inelastic proton scattering experiments were carried out to investigate the {gamma} decay of the 1{sup {minus}} state at an excitation energy of around 3.5 MeV in the {ital N}=82 nuclei {sup 142}Nd and {sup 144}Sm. {gamma}-ray branching ratios were determined from {gamma}-proton coincidences in both nuclei. The newly observed {gamma} decay of the dipole excitation at 3225 keV in {sup 144}Sm to the one-phonon states, in particular the (1{sup {minus}}{r_arrow}3{sub 1}{sup {minus}}) {ital E}2 transition to the octupole phonon state, is the first direct proof of the two-phonon character of the 1{sup {minus}} state in any {ital N}=82 nucleus. {copyright} {ital 1996 The American Physical Society.}
- Published
- 1996
44. An imaging of buried anomalies, using multi-sheet inversion
- Author
-
Avdeev, Dmitry B., Kuvshinov, Alexei V., and Pankratov, Oleg V.
- Published
- 1998
- Full Text
- View/download PDF
45. Current topics on light neutron-rich nuclei
- Author
-
M. Ishihara
- Subjects
Physics ,Nuclear physics ,Nuclear and High Energy Physics ,Nuclear Theory ,Physics::Accelerator Physics ,Neutron ,Halo ,Atomic physics ,Current (fluid) ,Nuclear Experiment ,Astrophysics::Galaxy Astrophysics ,Dipole excitation ,Radioactive beam - Abstract
Highlights of RIKEN radioactive beam experiments are reviewed. In particular the phenomena of giant soft dipole excitation of halo nuclei are closely discussed.
- Published
- 1995
46. Extremely neutron-rich nuclei and electro-magnetic excitations
- Author
-
M. Ishihara
- Subjects
Nuclear physics ,Physics ,Nuclear and High Energy Physics ,Nuclear Theory ,Coulomb ,Neutron ,Halo ,Atomic physics ,Nuclear Experiment ,Breakup ,Excitation ,Dipole excitation - Abstract
Coulomb excitations using radioactive beams are discussed. Applications of such reactions are described including soft dipole excitation of neutron halo nuclei, collective E2 excitation of 32 Mg and astrophysically interesting 8 B breakup.
- Published
- 1995
47. Binding Mechanism of a Neutron-Rich Nucleus 6He and Its Excited States
- Author
-
Shigeyoshi Aoyama, Shigeo Mukai, Kiyomi Ikeda, and Kiyoshi Katō
- Subjects
Physics ,medicine.anatomical_structure ,Physics and Astronomy (miscellaneous) ,Excited state ,Binding energy ,medicine ,Neutron ,State (functional analysis) ,Atomic physics ,Nucleus ,Resonance (particle physics) ,Scaling ,Dipole excitation - Abstract
By using the hybrid- TV model of the 4 He + n + n three-body system, the binding energy and excited states of "He are investigated. The binding energy 0.784 MeV is obtained for more realistic 4 He-n interaction. It is discussed that the n-n correlations, which are fully taken into account in the ECM bases, are very important to reproduce the binding energy of "He. The excited resonance states of the "He system are also calculated by applying the complex scaling method. The first excited z+ state obtained as a three-body resonance state is in good agreement with experiments. However, the excited 1- resonance states corresponding to the soft dipole excitation are not obtained at the low energy region.
- Published
- 1995
48. Higher order effects in electromagnetic dissociation of fast particles, a soluble model and application to 11Li
- Author
-
Gerhard Baur and Stefan Typel
- Subjects
Physics ,Nuclear and High Energy Physics ,Energy distribution ,Amplitude ,Projectile ,Coulomb ,Atomic physics ,Nuclear Experiment ,Nucleon ,Excitation ,Dipole excitation ,Dissociation (chemistry) - Abstract
A general method for the calculation of second order effects in the Coulomb dissociation is presented in the small ξ-limit avoiding the introduction of intermediate states. The amplitudes for a dipole excitation are analytically calculated in a simple model for the projectile with a zero-range force. The model is applied to the excitation of 11 Li at projectile energies of 28 and 800 MeV nucleon . The angular and energy distribution of the fragments and post-acceleration effects are examined in first and second order perturbation theory as well as the sudden approximation.
- Published
- 1994
49. Evidence for two-phonon giant-dipole excitation from inclusive measurements of 197Au target dissociation
- Author
-
John Hill, W. Brüchle, G. Wirth, E. Stiel, K. Sümmerer, Matthias Schädel, Thomas Aumann, M. Fauerbach, and Jens Volker Kratz
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Phonon ,Isoscalar ,Quadrupole ,Nuclear cross section ,Atomic physics ,Excitation ,Dipole excitation ,Dissociation (chemistry) - Abstract
Cross sections for the electromagnetic dissociation of 197 Au targets by 1.7 A GeV 20 Ne and 1 A GeV 88 Kr, 197 Au and 209 Bi beams have been measured by an activation method. Weizsacker-Williams calculations show that the experimental 1n cross sections can be understood by first order excitation of the giant dipole and the isoscalar giant quadrupole resonance. In contrast, the 3n cross sections show a much stronger Z proj - dependence, which can only be explained by a dominant contribution from two-phonon giant dipole excitation.
- Published
- 1994
50. Dipole excitation and scattering by spherical objects in GTEM cell
- Author
-
T. Rozzi, L. Zappelli, Luca Pierantoni, and R. De Leo
- Subjects
Physics ,Radiation ,business.industry ,Scattering ,Electromagnetic compatibility ,Dielectric ,Free space ,Condensed Matter Physics ,Dipole excitation ,Computational physics ,Dipole ,Optics ,GTEM cell ,Electrical and Electronic Engineering ,business ,Excitation - Abstract
The GTEM (GigaTEM) cell is proving a useful tool for characterizing the EM emission of objects under laboratory conditions. In order to enhance its practical use, however, it is essential to be able to identify and predict differences between tests in "open site" and in cell environment. The modes of the empty cell were previously reported. In this contribution, we address in the first time the problem of excitation by dipoles in the non uniform environment of the cell. Moreover, we present an analytical model of the scattering by a dielectric or conducting sphere in the cell. Numerical results are compared with experimental data, when possible, and with theoretical results for scattering by the same object in free space, showing very good agreement as regards the resonant frequencies. >
- Published
- 1994
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