We demonstrate the creation of robust localized zero-energy states that are induced into topologically trivial systems by insertion of a PT-symmetric defect with local gain and loss. A pair of robust localized states induced by the defect turns into zero-energy modes when the gain-loss contrast exceeds a threshold, at which the defect states encounter an exceptional point. Our approach can be used to obtain robust lasing or perfectly absorbing modes in any part of the system.
@article{arxiv.2006.04264,
title = {Robust localized zero-energy modes from locally embedded PT-symmetric defects},
author = {Fatemeh Mostafavi and Cem Yuce and Omar S. Magana-Loaiza and Henning Schomerus and Hamidreza Ramezani},
journal= {arXiv preprint arXiv:2006.04264},
year = {2020}
}