Semi-classical evaporative cooling: classical and quantum distributions

TL;DR

This paper introduces a semiclassical framework for modeling evaporative cooling in trapped atomic gases, integrating classical and quantum statistics to optimize cooling strategies and understand system behavior near degeneracy.

Contribution

It develops a unified analytical approach combining thermodynamics and phase-space distributions for diverse trapping potentials, enabling improved modeling of cooling processes.

Findings

Distinct behaviors of classical and quantum gases near degeneracy

Analytic expressions for particle number and energy in various traps

Guidance for optimizing evaporative cooling trajectories

Abstract

A unified semiclassical framework is presented to describe the evaporative cooling of trapped atomic gases, accounting for both classical and quantum statistics. By combining global thermodynamics with phase-space distributions, general analytic expressions for the particle number and internal energy are derived for a broad family of confining potentials. Building on these results, a recursive evaporation protocol is formulated based on truncated energy distributions, enabling stepwise mapping between successive thermodynamic states and revealing the system's degree of freedom governance over cooling efficiency. Numerical simulations of the systems highlight the contrasting behavior of classical and quantum systems as they approach degeneracy, with particularly distinctive signatures in quadrupole traps, due to their nonstandard phase-space scaling. The results provide a versatile theoretical tool for modeling evaporative cooling across experimentally relevant geometries and offer quantitative guidance for optimizing cooling trajectories in ultracold atomic systems.