Bragg scattering of Cooper pairs in an ultra-cold Fermi gas

TL;DR

This paper theoretically investigates Bragg scattering in an ultra-cold Fermi gas, revealing correlated pair scattering into a spherical shell in momentum space, distinct from single-particle scattering, and explains this phenomenon with an analytic model.

Contribution

It introduces a theoretical framework for understanding correlated Cooper pair scattering in a Fermi gas and predicts a unique scattering signature at half the usual Bragg momentum.

Findings

Correlated scattering forms a spherical shell in momentum space.

The scattered shell is centered at half the usual Bragg momentum.

The analytic model links scattering features to initial pair correlations.

Abstract

We present a theoretical treatment of Bragg scattering of a degenerate Fermi gas in the weakly interacting BCS regime. Our numerical calculations predict correlated scattering of Cooper pairs into a spherical shell in momentum space. The scattered shell of correlated atoms is centered at half the usual Bragg momentum transfer, and can be clearly distinguished from atoms scattered by the usual single-particle Bragg mechanism. We develop an analytic model that explains key features of the correlated-pair Bragg scattering, and determine the dependence of this scattering on the initial pair correlations in the gas.