Dynamical detection of topological charges

TL;DR

This paper introduces a universal dynamical method to identify topological phases by detecting topological charges through quench-induced spin dynamics, enabling efficient classification with minimal measurement requirements.

Contribution

It presents a novel scheme to classify topological phases by detecting monopole charges via non-equilibrium spin dynamics, requiring only a single spin component measurement.

Findings

Topological charges can be identified through quench dynamics.

The method simplifies detection by using only one spin component.

Numerical models demonstrate the scheme's feasibility.

Abstract

We propose a generic scheme to characterize topological phases via detecting topological charges by quench dynamics. A topological charge is defined as the chirality of a monopole at Dirac or Weyl point of spin-orbit field, and topological phases can be classified by total charges in the region enclosed by the so-called band-inversion surfaces (BISs). We show that both the topological monopoles and BISs can be identified by non-equilibrium spin dynamics caused by a sequence of quenches. From an emergent dynamical field given by time-averaged spin textures, the topological charges, as well as the topological invariant, can be readily obtained. An explicit advantage in this scheme is that only a single spin component needs to be measured to detect all the information of the topological phase. We numerically examine two realistic models, and propose a feasible experimental setup for the measurement. This work opens a new way to dynamically classify topological phases.