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

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.

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