Quantum Quenches in Chern Insulators

TL;DR

This paper investigates the non-equilibrium dynamics of Chern insulators, specifically the Haldane model, after quantum quenches, revealing persistent topological invariants and the evolution of edge currents and magnetization.

Contribution

It provides new insights into the dynamics of topological and edge states in Chern insulators following quantum quenches, highlighting the behavior of edge currents and topological invariants.

Findings

Chern number remains unchanged after quenches in infinite systems.

Edge currents relax to new equilibrium values post-quench.

Light-cone spreading of currents into the sample interior observed.

Abstract

We explore the non-equilibrium response of Chern insulators. Focusing on the Haldane model, we study the dynamics induced by quantum quenches between topological and non-topological phases. A notable feature is that the Chern number, calculated for an infinite system, is unchanged under the dynamics following such a quench. However, in finite geometries, the initial and final Hamiltonians are distinguished by the presence or absence of edge modes. We study the edge excitations and describe their impact on the experimentally-observable edge currents and magnetization. We show that, following a quantum quench, the edge currents relax towards new equilibrium values, and that there is light-cone spreading of the currents into the interior of the sample.