Optical response of superfluid state in dilute atomic Fermi-Dirac gases

TL;DR

This paper theoretically investigates how superfluidity in dilute atomic Fermi-Dirac gases affects their optical properties, revealing potential signatures of superfluidity and BCS pairing through optical linewidths and shifts.

Contribution

It introduces a theoretical framework for understanding optical responses in superfluid Fermi gases, highlighting the impact of BCS pairing on optical linewidths and local-field effects.

Findings

Superfluidity significantly alters optical linewidths and line shifts.

Local-field corrections can dominate over Lorentz-Lorenz shifts.

Optical properties may serve as signatures of superfluid state and BCS pairing.

Abstract

We theoretically study the propagation of light in a Fermi-Dirac gas in the presence of a superfluid state. BCS pairing between atoms in different hyperfine levels may significantly increase the optical linewidth and line shift of a quantum degenerate Fermi-Dirac gas and introduce a local-field correction that, under certain conditions, dramatically dominates over the Lorentz-Lorenz shift. These optical properties could possibly unambiguously sign the presence of the superfluid state and determine the value of the BCS order parameter.