Towards Strong-Coupling Generalization of the Bogoliubov Model

TL;DR

This paper introduces a new variational approach using the second-order reduced density matrix to address the thermodynamic inconsistency in dilute Bose gas models, enabling analysis with strong, singular interactions at zero temperature.

Contribution

It proposes a novel method that overcomes previous limitations, allowing strong-coupling analysis of dilute Bose gases with singular potentials.

Findings

Resolves thermodynamic inconsistency in Bose gas models

Enables treatment of strong, singular interactions like Lennard-Jones

Operates effectively at zero temperature

Abstract

The well-known results concerning a dilute Bose gas with the short-range repulsive interaction should be reconsidered due to a thermodynamic inconsistency of the method being basic to much of the present understanding of this subject and nonrelevant behaviour of the pair distribution function at small boson separations. The aim of our paper is to propose a new way of treating the dilute Bose gas with an arbitrary strong interaction. Using the reduced density matrix of the second order and a variational procedure, this way allows us to escape the inconsistency mentioned and operate with singular potentials like the Lennard-Jones one. All the consideration concerns the zero temperature.