Europhys. Lett., 70 (6), pp. 761-767 (2005)
DOI: 10.1209/epl/i2005-10051-1

Statistical mechanics of an optical phase space compressor

A. M. Dudarev^{1, 2}, M. Marder^{1, 2}, Q. Niu¹, N. J. Fisch³ and M. G. Raizen<sup>1, 2

1</sup>  Department of Physics, The University of Texas - Austin, TX, 78712-1081, USA
²  Center for Nonlinear Dynamics, The University of Texas Austin, TX 78712-1081, USA
³  Princeton Plasma Physics Laboratory, Princeton University Princeton, NJ 08543, USA

received 11 February 2005; accepted in final form 27 April 2005
published online 18 May 2005

Abstract
We describe the statistical mechanics of a new method to produce very cold atoms or molecules. The method results from trapping a gas in a potential well, and sweeping through the well a semi-permeable barrier, one that allows particles to leave but not to return. If the sweep is sufficiently slow, all the particles trapped in the well compress into a very cold gas. We derive analytical expressions for the velocity distribution of particles in the cold gas, compare these results with numerical simulations, and discuss limitations on reduction in energy due to imperfections of the barrier.

PACS
32.80.Pj - Optical cooling of atoms; trapping.
33.80.Ps - Optical cooling of molecules; trapping.

© EDP Sciences 2005