Low Temperature Physics: 43, 343 (2017); https://doi.org/10.1063/1.4979959
Fizika Nizkikh Temperatur: Volume 43, Number 3 (March 2017), p. 420-429    ( to contents , go back )

One more approach to the spectra of excitations in degenerate Bose gas with delta shaped interaction potential

V.B. Bobrov1,2, A.G. Zagorodny3, and S.A. Trigger1

1Joint Institute for High Temperatures, Russian Academy of Sciences,Izhorskaya St. 13, Bd. 2, Moscow 125412, Russia
E-mail: vic5907@mail.ru, satron@mail.ru

2Национальный исследовательский университет «МЭИ» ул. Красноказарменная, 14, г. Москва, 111250, Россия

3Boholyubov Institute for Theoretical Physics of the National Academy of Sciences of Ukraine 14-b Metrolohichna Str., Kiev 03680, Ukraine
E-mail: azagorodny@bitp.kiev.ua

Received Jule 11, 2016

Abstract

A formalism to describe the equilibrium Bose gas is proposed based on the consideration in the macroscopic, but a finite volume. The presence of Bose–Einstein condensate is taken into account through the off-diagonal long-range order in the transition to the thermodynamic limit. On this basis, a description of the degenerate Bose gas with delta-shaped interaction potential within the framework of the self-consistent Hartree–Fock approximation is given. Explicit expressions are obtained for the energy spectrum of single-particle and collective excitations.

PACS: 67.10.Ba Boson degeneracy;
PACS: 67.10.Fj Quantum statistical theory;
PACS: 67.25.de Thermodynamic properties;
PACS: 67.25.dt Sound and excitations.

Key words: degenerate Bose gas, Bose–Einstein condensate, collective excitations, single-particle excitations.

Published online: January 24, 2017

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