Measuring Non-Hermitian Topological Invariants Directly from Quench Dynamics

Kavli Affiliate: Long Zhang

| First 5 Authors: Xiao-Dong Lin, Long Zhang, , ,

| Summary:

While non-Hermitian (NH) topological phases and phenomena have been observed
across various quantum systems, directly measuring NH topological invariants
remains a significant challenge. In this study, we present a generic and
unified framework for the direct measurement of various NH topological
invariants in odd-dimensional systems through quench dynamics. We demonstrate
that in one-dimensional (1D) NH systems with sublattice symmetry, the line-gap
winding number and point-gap braiding degree can be extracted from the winding
patterns of a dynamically constructed field based on post-quench spin textures.
Specifically, line-gap topology is characterized by integer-valued winding,
whereas point-gap complex-band braiding is revealed by half-integer or integer
winding with abrupt jumps. We also extend our approach to higher-dimensional
winding numbers and non-Bloch topological invariants under open-boundary
conditions. Additionally, we propose a practical cold-atom setup to realize and
detect 1D NH topological phases, showing that our dynamical measurement scheme
is feasible in current experimental settings. This work paves the way for the
direct measurement of NH topological invariants in quantum systems.

| Search Query: ArXiv Query: search_query=au:”Long Zhang”&id_list=&start=0&max_results=3

Read More