Quasicondensation in 2D Interacting Bose Gas: Quantum Monte Carlo Study

TL;DR

This study uses Quantum Monte Carlo simulations to analyze correlations and quasicondensation phenomena in a 2D interacting Bose gas, revealing how local correlations evolve before the Kosterlitz-Thouless transition.

Contribution

It provides detailed Monte Carlo data on correlations in 2D Bose gases, highlighting the impact of interactions on quasicondensate fluctuations and local correlations.

Findings

Quasicondensate fluctuations influence local correlations before the transition.

The $1/m!$-effect amplitude is highly sensitive to interactions.

Local correlations change significantly prior to the Kosterlitz-Thouless transition.

Abstract

We present a detailed Monte Carlo study of correlations in an interacting two-dimensional Bose gas. The data for one-particle density matrix in coordinate representation are compared to the results for the local many-particle density correlators, which are responsible for the recombination rate in real experiments. We found that the appearance and growth of quasicondensate fluctuations changes local correlations between the particles well before the Kosterlitz-Thouless transition point. The amplitude of the $1/m!$-effect is very sensitive even to a rather moderate interaction, and is considerably smaller than its limiting value.