Itinerant ferromagnetism in 1D two-component Fermi gases

TL;DR

This paper investigates how adding an attractive odd-wave interaction to a 1D two-component Fermi gas with infinite contact repulsion can induce a ferromagnetic ground state, suggesting experimental realization with $^{40}$K atoms.

Contribution

It introduces a mechanism for itinerant ferromagnetism in 1D Fermi gases via symmetry-breaking odd-wave interactions, expanding understanding of magnetic phases in low-dimensional quantum gases.

Findings

Adding attractive odd-wave interactions induces ferromagnetism.

The proposed system is feasible with $^{40}$K atoms due to Feshbach resonances.

The 1D confinement reduces inelastic decay, aiding observation.

Abstract

We study a one-dimensional two-component atomic Fermi gas with an infinite intercomponent contact repulsion. It is found that adding an attractive resonant odd-wave interaction breaking the rotational symmetry one can make the ground state ferromagnetic. A promising system for the observation of this itinerant ferromagnetic state is a 1D gas of $^{40}$K atoms, where 3D $s$-wave and $p$-wave Feshbach resonances are very close to each other and the 1D confinement significantly reduces the inelastic decay.