Phonon-like excitations in the two-state Bose-Hubbard model
The spectrum of phonon-like collective excitations in the system of Bose-atoms in optical lattice (more generally, in the system of quantum particles described by the Bose-Hubbard model) is investigated. Such excitations appear due to displacements of particles with respect to their local equilibriu...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Institute for Condensed Matter Physics
2015-12-01
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| Series: | Condensed Matter Physics |
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| Online Access: | http://dx.doi.org/10.5488/CMP.18.43004 |
| _version_ | 1818550164047003648 |
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| author | I.V. Stasyuk O.V. Velychko O. Vorobyov |
| author_facet | I.V. Stasyuk O.V. Velychko O. Vorobyov |
| author_sort | I.V. Stasyuk |
| collection | DOAJ |
| description | The spectrum of phonon-like collective excitations in the system of Bose-atoms in optical lattice (more generally, in the system of quantum particles described by the Bose-Hubbard model) is investigated. Such excitations appear due to displacements of particles with respect to their local equilibrium positions. The two-level model taking into account the transitions of bosons between the ground state and the first excited state in potential wells, as well as interaction between them, is used. Calculations are performed within the random phase approximation in the hard-core boson limit. It is shown that excitation spectrum in normal phase consists of the one exciton-like band, while in the phase with BE condensate an additional band appears. The positions, spectral weights and widths of bands strongly depend on chemical potential of bosons and temperature. The conditions of stability of a system with respect to the lowering of symmetry and displacement modulation are discussed. |
| first_indexed | 2024-12-12T08:42:47Z |
| format | Article |
| id | doaj.art-cba2a480b95642eaaf1a281985147617 |
| institution | Directory Open Access Journal |
| issn | 1607-324X |
| language | English |
| last_indexed | 2024-12-12T08:42:47Z |
| publishDate | 2015-12-01 |
| publisher | Institute for Condensed Matter Physics |
| record_format | Article |
| series | Condensed Matter Physics |
| spelling | doaj.art-cba2a480b95642eaaf1a2819851476172022-12-22T00:30:42ZengInstitute for Condensed Matter PhysicsCondensed Matter Physics1607-324X2015-12-011844300410.5488/CMP.18.43004Phonon-like excitations in the two-state Bose-Hubbard modelI.V. StasyukO.V. VelychkoO. VorobyovThe spectrum of phonon-like collective excitations in the system of Bose-atoms in optical lattice (more generally, in the system of quantum particles described by the Bose-Hubbard model) is investigated. Such excitations appear due to displacements of particles with respect to their local equilibrium positions. The two-level model taking into account the transitions of bosons between the ground state and the first excited state in potential wells, as well as interaction between them, is used. Calculations are performed within the random phase approximation in the hard-core boson limit. It is shown that excitation spectrum in normal phase consists of the one exciton-like band, while in the phase with BE condensate an additional band appears. The positions, spectral weights and widths of bands strongly depend on chemical potential of bosons and temperature. The conditions of stability of a system with respect to the lowering of symmetry and displacement modulation are discussed.http://dx.doi.org/10.5488/CMP.18.43004Bose-Hubbard modelhard-core bosonsBose-Einstein condensationexcited bandphonons |
| spellingShingle | I.V. Stasyuk O.V. Velychko O. Vorobyov Phonon-like excitations in the two-state Bose-Hubbard model Condensed Matter Physics Bose-Hubbard model hard-core bosons Bose-Einstein condensation excited band phonons |
| title | Phonon-like excitations in the two-state Bose-Hubbard model |
| title_full | Phonon-like excitations in the two-state Bose-Hubbard model |
| title_fullStr | Phonon-like excitations in the two-state Bose-Hubbard model |
| title_full_unstemmed | Phonon-like excitations in the two-state Bose-Hubbard model |
| title_short | Phonon-like excitations in the two-state Bose-Hubbard model |
| title_sort | phonon like excitations in the two state bose hubbard model |
| topic | Bose-Hubbard model hard-core bosons Bose-Einstein condensation excited band phonons |
| url | http://dx.doi.org/10.5488/CMP.18.43004 |
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