Transport Across an Impurity in One Dimensional Quantum Liquids Far From Equilibrium

TL;DR

This paper investigates how a single impurity affects transport in a highly excited one-dimensional quantum liquid, revealing a quench-induced crossover and faster decoherence in current dynamics.

Contribution

It provides a theoretical analysis of impurity effects on transport in non-equilibrium quantum liquids using bosonization, highlighting the impact of global quenches.

Findings

Quench induces a crossover from conductor to insulator.

Faster decay of current towards steady-state after quench.

Global quench affects the quantum phase transition.

Abstract

We study the effect of a single impurity on the transport properties of a one dimensional quantum liquid highly excited away from its ground state by a sudden quench of the bulk interaction. In particular we compute the time dependent dc current to leading order in the impurity potential, using bosonization and starting both from the limit of a uniform system and from the one of two decoupled semi-infinite systems. Our results reveal that the nonequilibrium excitation of bulk modes induced by the global quench has important effects on the conductor-insulator quantum phase transition, which turns into a crossover for any small quench amplitude. In addition, the dynamics of the current displays a faster decay towards the steady-state as compared to the equilibrium case, a signature of quench-induced decoherence.