Defect production in quench from current-carrying non-equilibrium state

TL;DR

This paper investigates how initial current-carrying non-equilibrium states affect defect production during quantum critical driving, revealing a universal algebraic scaling at large initial currents, demonstrated via an exactly solvable Ising chain.

Contribution

It introduces a universal scaling law for defect production in current-carrying states during quantum critical dynamics, extending the quantum Kibble-Zurek mechanism.

Findings

Quantum Kibble-Zurek scaling is recovered at low initial currents.

A new universal algebraic scaling law emerges at high initial currents.

The theoretical predictions are validated using an exactly solvable Ising chain with Dzyaloshinskii-Moriya interaction.

Abstract

We consider the defect production of a quantum system, initially prepared in a current-carrying non-equilibrium state, during its unitary driving through a quantum critical point. At low values of the initial current, the quantum Kibble-Zurek scaling for the production of defects is recovered. However, at large values of the initial current, i.e., very far from an initial equilibrium situation, a universal scaling of the defect production is obtained which shows an algebraic dependence with respect to the initial current value. These scaling predictions are demonstrated by the exactly solvable Ising quantum chain where the current-carrying state is selected through the imposition of a Dzyaloshinskii-Moriya interaction term.