Ground-state reference systems for expanding correlated fermions in one dimension

TL;DR

This paper investigates the dynamics of strongly correlated fermions expanding in a one-dimensional lattice, demonstrating that transient correlations can be effectively modeled by equilibrium reference systems and identifying characteristic features in the momentum distribution.

Contribution

It introduces a method to describe transient correlations during fermion expansion using equilibrium reference systems, providing new insights into non-equilibrium dynamics.

Findings

Correlations in the transient regime are well described by equilibrium reference systems.

Expansion from a Mott insulator shows peaks at |k| ~ pi/2 in the momentum distribution.

Power-law correlations emerge during the expansion process.

Abstract

We study the sudden expansion of strongly correlated fermions in a one-dimensional lattice, utilizing the time-dependent density-matrix renormalization group method. Our focus is on the behavior of experimental observables such as the density, the momentum distribution function, and the density and spin structure factors. As our main result, we show that correlations in the transient regime can be accurately described by equilibrium reference systems. In addition, we find that the expansion from a Mott insulator produces distinctive peaks in the momentum distribution function at |k| ~ pi/2, accompanied by the onset of power-law correlations.