Non-Hermitian systems, which contain gain or loss, commonly host exceptional point degeneracies rather than the diabolic points found in Hermitian systems. We present a class of non-Hermitian lattice models with symmetry-stabilized diabolic points, such as Dirac or Weyl points. They exhibit non-Hermiticity-induced phenomena previously existing in the Hermitian regime, including topological phase transitions, Landau levels induced by pseudo-magnetic fields, and Fermi arc surface states. These behaviors are controllable via gain and loss, with promising applications in tunable active topological devices.
@article{arxiv.1912.10937,
title = {Non-Hermitian Dirac Cones},
author = {Haoran Xue and Qiang Wang and Baile Zhang and Y. D. Chong},
journal= {arXiv preprint arXiv:1912.10937},
year = {2020}
}