Non-Hermitian robust edge states in one-dimension: Anomalous localization and eigenspace condensation at exceptional points

2017/11/14 by V. M. Martinez Alvarez, J. E. Barrios Vargas, L. E. F. Foa Torres · 6 citations
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.97.121401

published as Phys. Rev. B 97, 121401 (2018) · 6 pages, 4 figures

arxiv created 2017/11/14 · arxiv updated 2018/03/14

Abstract

Capital to topological insulators, the bulk-boundary correspondence ties a topological invariant computed from the bulk (extended) states with those at the boundary, which are hence robust to disorder. Here we put forward an ordering unique to non-Hermitian lattices, whereby a pristine system becomes devoid of extended states, a property which turns out to be robust to disorder. This is enabled by a peculiar type of non-Hermitian degeneracy where a macroscopic fraction of the states coalesce at a single point with geometrical multiplicity of 1, that we call a phenomenal point.

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