Dynamic winding number for exploring band topology
Abstract
Topological invariants play a key role in the characterization of topological states. Due to the existence of exceptional points, it is a great challenge to detect topological invariants in non-Hermitian systems. We put forward a dynamic winding number, the winding of realistic observables in long-time average, for exploring band topology in both Hermitian and non-Hermitian two-band models via a unified approach. We build a concrete relation between dynamic winding numbers and conventional topological invariants. In one-dimension, the dynamical winding number directly gives the conventional winding number. In two-dimension, the Chern number relates to the weighted sum of dynamic winding numbers of all phase singularity points. This work opens a new avenue to measure topological invariants not requesting any prior knowledge of system topology via time-averaged spin textures.
Cite
@article{arxiv.1907.11348,
title = {Dynamic winding number for exploring band topology},
author = {Bo Zhu and Yongguan Ke and Honghua Zhong and Chaohong Lee},
journal= {arXiv preprint arXiv:1907.11348},
year = {2020}
}
Comments
6+7 pages, 3+4 figures