Pairing patterns in polarized unitary Fermi gases above the superfluid transition

TL;DR

This study investigates pairing mechanisms in polarized unitary Fermi gases above the superfluid transition, revealing that the superfluid state is likely homogeneous BCS-type across various polarizations.

Contribution

It introduces a non-perturbative analysis of pairing using pair-momentum distribution and shot-noise correlations in the high-temperature regime.

Findings

Pairs propagate as expected from BCS theory

Superfluid ground state is homogeneous and BCS-like

Pairing patterns above transition influence low-temperature condensates

Abstract

We non-perturbatively study pairing in the high-temperature regime of polarized unitary two-component Fermi gases by extracting the pair-momentum distribution and shot-noise correlations. Whereas the pair-momentum distribution allows us to analyze the propagation of pairs composed of one spin-up and one spin-down fermion, shot-noise correlations provide us with a tomographic insight into pairing correlations around the Fermi surfaces associated with the two species. Assuming that the dominant pairing patterns right above the superfluid transition also govern the formation of condensates in the low-temperature regime, our analysis suggests that the superfluid ground state is homogeneous and of the Bardeen-Cooper-Schrieffer-type over a wide range of polarizations.