Abstract

In the last few years there has been a revived hype around non-Hermitian lattices ([1,2,3]), systems where non Hermiticity is used to model gains and losses (as in photonic or acoustic systems) or the effect of interactions, and, in particular the search for topological states in these systems. In this talk I will provide a personal overview on this topic with a focus on how a macroscopic fraction of the states become localized at a boundary [4], now called the non-hermitian skin effect [5], and open issues in the (older) problem of chiral state conversion [6].
[1] R. Lin, T. Tai, L. Li, and C. H. Lee, Frontiers of Physics 18, 53605 (2023). http://dx.doi.org/10.1007/s11467-023-1309-z

[2] V. M. Martinez Alvarez, J. E. Barrios Vargas, M. Berdakin, and L. E. F. Foa Torres, Eur. Phys. J. Spec. Top. (2018), https://doi.org/10.1140/epjst/e2018-800091-5

[3] L. E. F. Foa Torres, Journal of Physics: Materials 3, 014002 (2020), https://iopscience.iop.org/article/10.1088/2515-7639/ab4092/meta

[4] V. M. Martinez Alvarez, J. E. Barrios Vargas, and L. E. F. Foa Torres, Phys. Rev. B 97, 121401(R) (2018). https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.121401

[5] S. Yao and Z. Wang, Phys. Rev. Lett. 121, 086803 (2018). https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.086803

[6] W. D. Heiss, Journal of Physics A: Mathematical and Theoretical 45, 444016 (2012). http://dx.doi.org/10.1088/1751-8113/45/44/444016