Direct observation of the Fermi surface in an ultracold atomic gas
Abstract
The ideal (i.e. noninteracting), homogeneous Fermi gas, with its characteristic sharp Fermi surface in the momentum distribution, is a fundamental concept relevant to the behavior of many systems. With trapped Fermi gases of ultracold atoms, one can realize and probe a nearly ideal Fermi gas, however these systems have a nonuniform density due to the confining potential. We show that the effect of the density variation, which typically washes out any semblance of a Fermi surface step in the momentum distribution, can be mitigated by selectively probing atoms near the center of a trapped gas. With this approach, we have directly measured a Fermi surface in momentum space for a nearly ideal gas, where the average density and temperature of the probed portion of the gas can be determined from the location and sharpness of the Fermi surface.
Cite
@article{arxiv.1204.0048,
title = {Direct observation of the Fermi surface in an ultracold atomic gas},
author = {T. E. Drake and Y. Sagi and R. Paudel and J. T. Stewart and J. P. Gaebler and D. S. Jin},
journal= {arXiv preprint arXiv:1204.0048},
year = {2012}
}