Harter, Andrew K.Lee, Tony E.Joglekar, Yogesh N.2017-01-312017-01-312016-06Harter, A. K., Lee, T. E., & Joglekar, Y. N. (2016). PT-breaking threshold in spatially asymmetric Aubry-André and Harper models: Hidden symmetry and topological states. Physical Review A, 93(6), 062101.https://hdl.handle.net/1805/11886Aubry-André-Harper lattice models, characterized by a reflection-asymmetric sinusoidally varying nearest-neighbor tunneling profile, are well known for their topological properties. We consider the fate of such models in the presence of balanced gain and loss potentials ±iγ located at reflection-symmetric sites. We predict that these models have a finite PT-breaking threshold only for specific locations of the gain-loss potential and uncover a hidden symmetry that is instrumental to the finite threshold strength. We also show that the topological edge states remain robust in the PT-symmetry-broken phase. Our predictions substantially broaden the possible experimental realizations of a PT-symmetric system.enPublisher PolicyArticle