Non-local pair correlations in the 1D Bose gas at finite temperature

TL;DR

This paper provides a comprehensive analysis of two-particle correlations in a 1D Bose gas at finite temperature, combining analytic and numerical methods across various interaction strengths and temperature regimes.

Contribution

It introduces combined perturbative and numerical approaches to study spatial correlations in the 1D Bose gas at finite temperature, covering all interaction and temperature regimes.

Findings

Observation of thermally induced bunching and interaction-induced antibunching effects.

Validation of perturbative methods at strong and weak coupling regimes.

Numerical results revealing complex correlation behaviors across regimes.

Abstract

The behavior of the spatial two-particle correlation function is surveyed in detail for a uniform 1D Bose gas with repulsive contact interactions at finite temperatures. Both long-, medium-, and short-range effects are investigated. The results span the entire range of physical regimes, from ideal gas, to strongly interacting, and from zero temperature to high temperature. We present perturbative analytic methods, available at strong and weak coupling, and first-principle numerical results using imaginary time simulations with the gauge-P representation in regimes where perturbative methods are invalid. Nontrivial effects are observed from the interplay of thermally induced bunching behavior versus interaction induced antibunching.