First principles calculation of topological invariants of non-Hermitian photonic crystals

@article{Prudncio2020FirstPC,
  title={First principles calculation of topological invariants of non-Hermitian photonic crystals},
  author={Filipa R. Prud{\^e}ncio and M{\'a}rio G. Silveirinha},
  journal={arXiv: Applied Physics},
  year={2020}
}
The Chern topological numbers of a material platform are usually written in terms of the Berry curvature, which depends on the normal modes of the system. Here, we use a gauge invariant Green's function method to determine from first principles the topological invariants of photonic crystals. The proposed formalism does not require the calculation of the photonic band-structure, and can be easily implemented using the operators obtained with a standard plane-wave expansion. Furthermore, it is… 

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