Direct Simulation Monte Carlo method for cold atom dynamics: classical Boltzmann equation in the quantum collision regime

TL;DR

This paper introduces a DSMC method tailored for simulating the complex nonequilibrium dynamics of ultra-cold gases, incorporating quantum effects beyond s-wave scattering, and demonstrates its application in modeling high-energy collisions and rethermalization.

Contribution

The paper develops a novel DSMC approach for ultra-cold gases that includes quantum collision effects beyond s-wave scattering, enabling realistic simulations of experimental scenarios.

Findings

Successfully simulates high-energy collisions of thermal clouds

Demonstrates the method's ability to model rethermalization dynamics

Validates the approach against experimental conditions

Abstract

In this paper we develop a direct simulation Monte Carlo (DSMC) method for simulating highly nonequilibrium dynamics of nearly degenerate ultra-cold gases. We show that our method can simulate the high-energy collision of two thermal clouds in the regime observed in experiments [Thomas, et al. Phys. Rev. Lett. \textbf{93}, 173201 (2004)], which requires the inclusion of beyond s-wave scattering. We also consider the long-time dynamics of this system, demonstrating that this would be a practical experimental scenario for testing the Boltzmann equation and studying rethermalization.