Spin segregation via dynamically induced long-range interaction in a system of ultracold fermions

TL;DR

This paper predicts that a one-dimensional ultracold fermion system with an initial spiral spin configuration will exhibit spin segregation over time due to a dynamically induced long-range interaction, even at weak interactions.

Contribution

It introduces a theoretical framework showing how exchange interactions and harmonic trapping lead to spin segregation via dynamically induced long-range interactions.

Findings

Spin segregation occurs in weakly interacting ultracold fermions.

The effect is robust across various parameters.

Long-range interactions are dynamically generated by the trap and exchange effects.

Abstract

We investigate theoretically the time evolution of a one-dimensional system of spin-1/2 fermions in a harmonic trap after, initially, a spiral spin configuration far-from equilibrium is created. We predict a spin segregation building up in time already for weak interaction under realistic experimental conditions. The effect relies on the interplay between exchange interaction and the harmonic trap, and it is found for a wide range of parameters. It can be understood as a consequence of an effective, dynamically induced long-range interaction that is derived by integrating out the rapid oscillatory dynamics in the trap.