Bose-Einstein condensation and/or modulation of "displacements" in the two-state Bose-Hubbard model
Instabilities resulting in Bose-Einstein condensation and/or modulation of “displacements” in a system of quantum particles described by a two-state Bose-Hubbard model (with an allowance for the interaction between particle displacements on different lattice sites) are investigated. A possibility o...
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| Date: | 2018 |
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| Main Authors: | , |
| Format: | Article |
| Language: | English |
| Published: |
Інститут фізики конденсованих систем НАН України
2018
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| Series: | Condensed Matter Physics |
| Online Access: | http://dspace.nbuv.gov.ua/handle/123456789/157050 |
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| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Bose-Einstein condensation and/or modulation of "displacements" in the two-state Bose-Hubbard model / I.V. Stasyuk, O.V. Velychko // Condensed Matter Physics. — 2018. — Т. 21, № 2. — С. 23002: 1–17. — Бібліогр.: 24 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| Summary: | Instabilities resulting in Bose-Einstein condensation and/or modulation of “displacements” in a system of quantum particles described by a two-state Bose-Hubbard model (with an allowance for the interaction between
particle displacements on different lattice sites) are investigated. A possibility of modulation, which doubles
the lattice constant, as well as the uniform displacement of particles from equilibrium positions are studied.
Conditions for realization of the mentioned instabilities and phase transitions into the SF phase and into the
“ordered” phase with frozen displacements are analyzed. The behaviour of order parameters is investigated
and phase diagrams of the system are calculated both analytically (ground state) and numerically (at non-zero
temperatures). It is revealed that the SF phase can appear as an intermediate one between the normal and
“ordered” phases, while a supersolid phase is thermodynamically unstable and does not appear. The relation of
the obtained results to the lattices with the double-well local potentials is discussed. |
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