Cold Fermi atomic gases in a pumped optical resonator

TL;DR

This paper investigates the nonlinear dynamics of fully polarized ultracold Fermi gases in a pumped optical cavity, revealing a novel instability driven by matter wave fluctuations that differs from traditional optical bistability.

Contribution

It introduces a new type of intracavity intensity instability caused by matter wave fluctuations in Fermi gases, expanding understanding of atom-cavity nonlinear interactions.

Findings

Identifies a unique instability driven by matter wave fluctuations.

Shows the instability occurs even when atomic dipole is proportional to the cavity field.

Reveals the instability's dependence on atomic density fluctuations.

Abstract

We study systems of fully polarized ultracold atomic gases obeying Fermi statistics. The atomic transition interacts dispersively with a mode of a standing-wave cavity, which is coherently pumped by a laser. In this setup, the intensity of the intracavity field is determined by the refractive index of the atomic medium, and thus by the atomic density distribution. Vice versa, the density distribution of the atom is determined by the cavity field potential, whose depth is proportional to the intracavity field amplitude. In this work we show that this nonlinearity leads to an instability in the intracavity intensity that differs substantially from dispersive optical bistability, as this effect is already present in the regime, where the atomic dipole is proportional to the cavity field. Such instability is driven by the matter waves fluctuations and exhibits a peculiar dependence on the fluctuations in the atomic density distribution.