NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Optimization of collisional Feshbach cooling of an ultracold non degenerate gas
Published
Author(s)
Marlon Nuske, L. Mathey, Eite Tiesinga
Abstract
We optimize a collision-induced cooling process for ultracold atoms in the nondegenerate regime. It makes use of a Feshbach resonance, instead of rf radiation in evaporative cooling, to selectively expel hot atoms from a trap. Using functional minimization we analytically show that for the optimal cooling process the resonance energy must be tuned such that it linearly follows the temperature. Here, optimal cooling is defined as maximizing the phase-space density after a fixed cooling duration. The analytical results are confirmed by numerical Monte-Carlo simulations. In order to simulate more realistic experimental conditions, we show that background losses do not change our conclusions, while additional non-resonant two-body losses make a lower initial resonance energy with non-linear dependence on temperature preferable.
Nuske, M.
, Mathey, L.
and Tiesinga, E.
(2015),
Optimization of collisional Feshbach cooling of an ultracold non degenerate gas, Physical Review A, [online], https://doi.org/10.1103/PhysRevA.91.043626, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=917900
(Accessed October 10, 2025)