Concomitant Modulated Superfluidity In Polarized Fermionic Gases

TL;DR

This paper uses advanced numerical methods to explore superfluid states in polarized fermionic gases, revealing metastable phases and supporting the existence of the Fulde-Ferrel-Larkin-Ovchinnikov state, thus clarifying experimental discrepancies.

Contribution

It introduces a fully self-consistent 3D numerical approach to study large fermionic systems, demonstrating the emergence of metastable superfluid states and supporting the FFLO phase.

Findings

Identification of metastable superfluid solutions in elongated traps

Support for the FFLO state in high aspect ratio geometries

Resolution of experimental discrepancies regarding polarized fermionic gases

Abstract

Recent groundbreaking experiments studying the effects of spin polarization on pairing in unitary Fermi gases encountered mutual qualitative and quantitative discrepancies which seem to be a function of the confining geometry. Using novel numerical algorithms we study the solution space for a 3-dimensional fully self-consistent formulation of realistic systems with up to $10^{5}$ atoms. A study of the three types of solutions obtained demonstrates a tendency towards metastability as the confining geometry is elongated. One of these solutions, which is consistent with Rice experiments at high trap aspect ratio, supports a state strikingly similar to the long sought Fulde-Ferrel-Larkin-Ovchinnikov state. Our study helps to resolve the long-standing controversy concerning the discrepancies between the findings from two different experimental groups and highlights the versatility of actual-size numerical calculations for investigating inhomogeneous fermionic superfluids.