Trapped Two-Dimensional Fermi Gases with Population Imbalance

TL;DR

This paper investigates the ground state configurations of population imbalanced Fermi gases in two dimensions under confinement, revealing phase structures and transition behaviors across the BEC-BCS crossover at zero temperature.

Contribution

It provides a theoretical analysis of the phase structure and transitions in trapped 2D imbalanced Fermi gases using mean-field theory and local-density approximation.

Findings

Trapped systems are either fully normal or have a superfluid core with a normal shell.

Trap configurations can undergo continuous transitions with changing imbalance.

Superfluid phases slow down thermal equilibration at low temperatures.

Abstract

We study population imbalanced Fermi mixtures under quasi-two-dimensional confinement at zero temperature. Using mean-field theory and the local-density approximation, we study the ground state configuration throughout the BEC-BCS crossover. We find the trapped system to be either fully normal or to consist of a superfluid core surrounded by a normal shell, which is itself either fully or partially polarized. Upon changing the trap imbalance, the trap configuration may undergo continuous transitions between the different ground states. Finally, we argue that thermal equilibration throughout the trap will be considerably slowed down at low temperatures when a superfluid phase is present.