Interaction effects on dynamic correlations in non-condensed Bose gases

TL;DR

This paper investigates how interactions influence the frequency-dependent correlations in non-condensed Bose gases, focusing on single-particle and spin-current fluctuations, revealing their dependence on relaxation times.

Contribution

It provides the first detailed analysis of dynamic correlation functions in non-condensed Bose gases, linking spectral features to interaction-induced relaxation times.

Findings

Power spectrum depends on interatomic interactions and relaxation times.

Single-particle and spin-current correlations are characterized.

Interaction effects on dynamic correlations are quantitatively described.

Abstract

We consider dynamic, i.e., frequency-dependent, correlations in non-condensed ultracold atomic Bose gases. In particular, we consider the single-particle correlation function and its power spectrum. We compute this power spectrum for a one-component Bose gas, and show how it depends on the interatomic interactions that lead to a finite single-particle relaxation time. As another example, we consider the power spectrum of spin-current fluctuations for a two-component Bose gas and show how it is determined by the spin-transport relaxation time.