Effective microscopic models for sympathetic cooling of atomic gases

TL;DR

This paper develops new microscopic models tailored for sympathetic cooling of ultracold atomic gases, addressing the limitations of traditional heat bath models by incorporating atomic trap specifics and nonlinearity.

Contribution

It introduces adapted interaction Hamiltonians for ultracold gases, enabling molecular dynamics simulations and stability analysis for sympathetic cooling optimization.

Findings

Models accommodate well-defined trap frequencies.

Stability analysis identifies effective parameter ranges.

Simulations aid in optimizing Bose-Fermi mixture cooling.

Abstract

Thermalization of a system in the presence of a heat bath has been the subject of many theoretical investigations especially in the framework of solid-state physics. In this setting, the presence of a large bandwidth for the frequency distribution of the harmonic oscillators schematizing the heat bath is crucial, as emphasized in the Caldeira-Leggett model. By contrast, ultracold gases in atomic traps oscillate at well-defined frequencies and therefore seem to lie outside the Caldeira-Leggett paradigm. We introduce interaction Hamiltonians which allow us to adapt the model to an atomic physics framework. The intrinsic nonlinearity of these models differentiates them from the original Caldeira-Leggett model and calls for a nontrivial stability analysis to determine effective ranges for the model parameters. These models allow for molecular dynamics simulations of mixtures of ultracold gases, which is of current relevance for optimizing sympathetic cooling in degenerate Bose-Fermi mixtures.