Quench dynamics of spin-imbalanced Fermi-Hubbard model in one dimension

TL;DR

This paper investigates the nonequilibrium dynamics of a one-dimensional spin-imbalanced Fermi-Hubbard model after a quantum quench, revealing how different initial states lead to thermalized or pre-thermalized stationary states, useful for identifying the FFLO phase.

Contribution

It provides a detailed analysis of post-quench dynamics starting from BCS and FFLO states, highlighting the dependence of stationary states on initial conditions and proposing a method to identify the FFLO phase.

Findings

Gapped BCS state leads to thermalization with an effective temperature.

Gapless FFLO state reaches a pre-thermalized state far from equilibrium.

Post-quench dynamics can serve as a fingerprint for FFLO phase identification.

Abstract

We study a nonequilibrium dynamics of a one-dimensional spin-imbalanced Fermi-Hubbard model following a quantum quench of on-site interaction, realizable, for example, in Feshbach-resonant atomic Fermi gases. We focus on the post-quench evolution starting from the initial BCS and FuldeFerrell-Larkin-Ovchinnikov (FFLO) ground states and analyze the corresponding spin-singlet, spin-triplet, density-density, and magnetization-magnetization correlation functions. We find that beyond a light-cone crossover time, rich post-quench dynamics leads to thermalized and pre-thermalized stationary states that display strong dependence on the initial ground state. For initially gapped BCS state, the long-time stationary state resembles thermalization with the effective temperature set by the initial value of the Hubbard interaction. In contrast, while the initial gapless FFLO state reaches a stationary pre-thermalized form, it remains far from equilibrium. We suggest that such post-quench dynamics can be used as a fingerprint for identification and study of the FFLO phase.