Multiple-quantized vortices in rotating LOFF state of ultracold Fermi superfluid gas

TL;DR

This paper investigates how rotation induces multiple-quantized vortices in a polarized ultracold Fermi superfluid near the LOFF phase, revealing oscillating critical velocities and reentrant superfluidity due to Landau level population effects.

Contribution

It demonstrates the emergence of multiple-quantized vortices in a rotating LOFF state of ultracold Fermi gases, highlighting the role of Landau level population in this phenomenon.

Findings

Critical angular velocity oscillates with temperature and population imbalance.

Vortex lattices with multiple circulation quanta form in the LOFF state.

Reentrant superfluid phases occur near the Lifshitz critical point.

Abstract

A rotating ultracold S-wave superfluid Fermi gas is considered, when the population imbalance (or equivalently the mismatch in chemical potentials) corresponds to the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) state in the vicinity of the Lifshitz critical point. It is shown that under these conditions the critical angular velocity in two-dimensional systems is an oscillating function of temperature and population imbalance giving rise to reentrant superfluid phases. This leads to vortex lattices with multiple-quantized circulation quanta. The reason for this behavior is the population by Cooper pairs of the Landau levels above the lowest one.