Quench dynamics of dipolar fermions in a one-dimensional harmonic trap

TL;DR

This paper investigates the non-equilibrium dynamics of a few dipolar fermions in a one-dimensional harmonic trap, revealing how dipolar interactions induce chaos and lead to relaxation and thermalization after a quench.

Contribution

It provides the first exact diagonalization study of dipolar fermions in a harmonic trap, highlighting the role of dipolar interactions in chaotic dynamics and thermalization.

Findings

Dipolar interactions cause rapid relaxation to non-thermal states.

Level spacing analysis indicates chaotic behavior due to dipolar interactions.

System remains oscillatory without dipolar interactions, near integrability.

Abstract

We study a system of few fermions in a one-dimensional harmonic trap, and focus on the case of dipolar majority particles in contact with a single impurity. The impurity is used both for quenching the system, and for tracking the system evolution after the quench. Employing exact diagonalization, we investigate relaxation and thermalization properties. In the absence of dipolar interactions, the system is near integrability, and the dynamics remains oscillatory even on long time scales. On the other hand, repulsive as well as attractive dipolar interactions lead to quick relaxation to the diagonal ensemble average which is significantly different from corresponding thermal averages. A Wigner-shaped level spacing distribution indicates level repulsion and thus chaotic dynamical behavior due to the presence of dipolar interactions.