Modern Physics Letters B

UPPER BOUND ON THE TWO-POINT CORRELATION FUNCTION OF A SYSTEM OF COUPLED ANHARMONIC OSCILLATORS

Nikolay N. Bogolubov, Дмитрий Петрович Санкович

Published Jan 10, 1991• 3 citations

Abstract

A quantum system of coupled anharmonic oscillators on v-dimensional hypercubic lattice is considered. The upper bound on the pair correlator is obtained. For the representation of creation-annihilation operators this system corresponds to a lattice boson gas model with δ-type repulsion. We prove the existence of Bose condensation at sufficiently low temperatures, and hence of a phase transition in three or more dimensions. An estimate of the critical temperature is obtained.

DOI: 10.1142/s0217984991000071

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