Noise correlations of a strongly attractive spin-1/2 Fermi gas in an optical lattice

TL;DR

This paper investigates density correlations in a strongly attractive spin-1/2 Fermi gas in an optical lattice, revealing distinct correlation signatures for Bose-Einstein condensate and Mott insulator phases, aiding experimental phase identification.

Contribution

It provides a detailed analysis of quantum fluctuation effects on density correlations in both phases of the system, highlighting their contrasting features.

Findings

Singular peaks in correlations for Bose-Einstein condensate

Sharp dips in correlations for Mott insulator

Correlation patterns can distinguish phases experimentally

Abstract

We calculate density-density correlations of an expanding gas of strongly attractive ultra-cold spin-1/2 fermions in an optical lattice. The phase diagram of the tightly bound fermion pairs exhibits a Bose-Einstein condensed state and a Mott insulating state with a single molecule per lattice site. We study the effects of quantum fluctuations on the correlations in both phases and show that they are especially important in the Bose-Einstein condensate state, leading to the appearance of singular peaks. In the Mott insulating state the correlations are characterized by sharp dips. This can be utilized in experiments to distinguish between these two phases.