Publications Details

Spectral localizer for line-gapped non-Hermitian systems

Cerjan, Alexander W.; Koekenbier, Lars; Schulz-Baldes, Hermann

Short-ranged and line-gapped non-Hermitian Hamiltonians have strong topological invariants given by an index of an associated Fredholm operator. It is shown how these invariants can be accessed via the signature of a suitable spectral localizer. Here, this numerical technique is implemented in an example with relevance to the design of topological photonic systems, such as topological lasers.