Quasicondensation in Two-Dimensional Fermi Gases

Phys Rev Lett. 2015 Dec 11;115(24):240401. doi: 10.1103/PhysRevLett.115.240401. Epub 2015 Dec 9.

Abstract

In this paper we follow the analysis and protocols of recent experiments, combined with simple theory, to arrive at a physical understanding of quasi-condensation in two dimensional Fermi gases. A key signature of quasi-condensation, which contains aspects of Berezinskiĭ-Kosterlitz-Thouless behavior, is a strong zero momentum peak in the pair momentum distribution. Importantly, this peak emerges at a reasonably well defined onset temperature. The resulting phase diagram, pair momentum distribution, and algebraic power law decay are compatible with recent experiments throughout the continuum from BEC to BCS.