Wu, Ya-JieHou, Junpeng2020-03-312020-03-312019-06-122469-9926http://dx.doi.org/10.1103/PhysRevA.99.062107https://hdl.handle.net/10735.1/7735Understanding how local potentials affect system eigenmodes is crucial for experimental studies of nontrivial bulk topology. Recent studies have discovered many exotic and highly nontrivial topological states in non-Hermitian systems. As such, it would be interesting to see how non-Hermitian systems respond to local perturbations. In this work we consider chiral and particle-hole-symmetric non-Hermitian systems on a bipartite lattice, including the Su-Schrieer-Heeger model and photonic graphene, and find that a disordered local potential could induce bound states evolving from the bulk. When the local potential on a single site becomes infinite, which renders a lattice vacancy, chiral-symmetry-protected zero-energy mode and particle-hole-symmetry-protected bound states with purely imaginary eigenvalues emerge near the vacancy. These modes are robust against any symmetry-preserved perturbations. Our work generalizes the symmetry-protected localized states to non-Hermitian systems. © 2019 American Physical Society.en©2019 American Physical SocietyEigenvaluesEigenfunctionsParticles (Nuclear physics)—ChiralityTopologyEigenfunctionsHermitian structuresarticleWu, Y. -J, and J. Hou. 2019. "Symmetry-protected localized states at defects in non-Hermitian systems." Physical Review A 99(6): art. 062107, doi: 10.1103/PhysRevA.99.062107996