Kavli Affiliate: Long Zhang
| First 5 Authors: Xiao-Dong Lin, Xiao-Dong Lin, , ,
| Summary:
The accurate determination of non-Hermitian (NH) topological invariants plays
a central role in the study of NH topological phases. In this work, we propose
a general framework for directly measuring NH topological invariants in
even-dimensional systems with real line gaps through quench dynamics. Our
approach hinges on constructing an auxiliary Hermitian matrix topologically
equivalent to the original NH Hamiltonian, enabling topological
characterization via reduced-dimensional momentum subspaces called
band-inversion surfaces (BISs). A key insight lies in the emergence of chiral
symmetry in the NH Hamiltonian specifically on BISs — a critical property that
allows extension of the dynamical characterization scheme previously developed
for odd-dimensional NH systems with chiral or sublattice symmetry [Lin et al.,
Phys. Rev. Res. 7, L012060 (2025)]. We show that NH topological invariants can
be extracted from the winding patterns of a dynamical field constructed from
post-quench spin textures on BISs. We demonstrate our approach through a
detailed analysis of NH Chern insulators and then extend the framework to
higher even-dimensional systems by introducing second-order BISs for
characterization. The framework is also generalized to imaginary line-gapped
topological phases. This work establishes an experimentally accessible protocol
for detecting NH topological invariants in quantum platforms.
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