Simulation method for evaporative cooling of trapped Bose gases at finite temperatures

TL;DR

This paper presents a simulation method for evaporative cooling of trapped Bose-Einstein condensates at finite temperatures, incorporating the Zaremba-Nikuni-Griffin formalism and test particle techniques to model condensate growth and vortex formation.

Contribution

It introduces a novel numerical approach that combines the ZNG formalism with test particle simulation to accurately model evaporative cooling dynamics at finite temperatures.

Findings

Successfully models condensate growth during evaporative cooling

Simulates vortex lattice formation in rotating thermal clouds

Demonstrates the effectiveness of the method in capturing finite-temperature effects

Abstract

We develop a simulation method for evaporative cooling of trapped Bose-Einstein condensate at finite temperatures using Zaremba-Nikuni-Griffin (ZNG) formalism. ZNG formalism includes the generalized GP equation and a semiclassical kinetic equation for the thermal cloud, which treats the excitations semiclassically within the Hartree Fock approximation. The generalized GP equation includes the mean field due to the thermal cloud and the source term associated with collisions between the condensate and the thermal cloud. Our method is based on the numerical approach developed by Jackson and Zaremba, which simulates the kinetic equation using test particles. A key point of our method is to mimic the evaporative cooling process by eliminating the test particles with high energy. We show that our method successfully describes condensate growth during evaporative cooling. We also numerically simulate vortex lattice formation during evaporative cooling in the presence of the rotating thermal cloud.