Fast optimal frictionless atom cooling in harmonic traps

TL;DR

The paper introduces a rapid, frictionless atom cooling method in harmonic traps that preserves quantum state populations without phase-space compression, outperforming previous optimal-control approaches in speed.

Contribution

It presents a novel fast cooling technique that maintains quantum populations and can involve transient expulsive potentials, surpassing existing methods in efficiency.

Findings

Cooling times shorter than previous optimal-control methods

Method preserves populations without phase-space compression

Transient expulsive potentials may be used for faster cooling

Abstract

A method is proposed to cool down atoms in a harmonic trap without phase-space compression as in a perfectly slow adiabatic expansion, i.e., keeping the populations of the instantaneous initial and final levels invariant, but in a much shorter time. This may require that the harmonic trap becomes an expulsive parabolic potential in some time interval. The cooling times achieved are also shorter than previous minimal times using optimal-control bang-bang methods and real frequencies.