Vortex Core Structure in Neutral Fermion Superfluids with Population Imbalance

TL;DR

This paper investigates the vortex core structure in population-imbalanced neutral fermion superfluids near a Feshbach resonance, revealing that the core's visibility depends on minority species density profiles, offering new experimental insights.

Contribution

It introduces the theoretical analysis of vortex core filling in imbalanced fermion superfluids and proposes a novel method to observe the core via minority density profiles.

Findings

Vortex cores are filled and less visible in density profiles due to majority species occupation.

Minority density profiles can reveal vortex cores through phase contrast imaging.

The study uncovers low-lying fermionic bound states in vortex cores.

Abstract

Quantized vortex core structure is theoretically investigated in Fermion superfluids with population imbalance for two atom species of neutral atom clouds near a Feshbach resonance. In contrast with vortex core in balance case where the quantum depletion makes a vortex visible through the density profile measurement, the vortex core is filled in and becomes less visible because the quantized discrete bound states are occupied exclusively by the majority species. Yet it is shown that the core can be visible through the minority density profile experiment using phase contrast imaging, revealing an interesting opportunity to examine low-lying Fermionic core bound states unexplored so far.