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arXiv · 1712.02444

Effects of non-Hermitian perturbations on Weyl Hamiltonians with arbitrary topological charges

Alexander Cerjan·Meng Xiao·Luqi Yuan·Shanhui Fan
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Abstract

We provide a systematic study of non-Hermitian topologically charged systems. Starting from a Hermitian Hamiltonian supporting Weyl points with arbitrary topological charge, adding a non-Hermitian perturbation transforms the Weyl points to one-dimensional exceptional contours. We analytical prove that the topological charge is preserved on the exceptional contours. In contrast to Hermitian systems, the addition of gain and loss allows for a new class of topological phase transition: when two oppositely charged exceptional contours touch, the topological charge can dissipate without opening a gap. These effects can be demonstrated in realistic photonics and acoustics systems.

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Alexander Cerjan, Meng Xiao, Luqi Yuan, Shanhui Fan. 2017-12-06. Effects of non-Hermitian perturbations on Weyl Hamiltonians with arbitrary topological charges. https://doi.org/10.1103/physrevb.97.075128

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