paper

Non-Hermiticity induces localization: good and bad resonances in power-law random banded matrices

arXiv:2302.00015 · doi:10.1103/PhysRevB.108.L180202

Abstract

The power-law random banded matrix (PLRBM) is a paradigmatic ensemble to study the Anderson localization transition (AT). In -dimension the PLRBM are random matrices with algebraic decaying off-diagonal elements , having AT at . In this work, we investigate the fate of the PLRBM to non-Hermiticity. We consider the case where the random on-site diagonal potential takes complex values, mimicking an open system, subject to random gain-loss terms. We provide an analytical understanding of the model by generalizing the Anderson-Levitov resonance counting technique to the non-Hermitian case. This generalization identifies two competing mechanisms due to non-Hermiticity: one favoring localization and the other delocalization. The competition between the two gives rise to AT at . The value of the critical depends on the strength of the on-site potential, reminiscent of Hermitian disordered short-range models in . Within the localized phase, the wave functions are algebraically localized with an exponent even for . This result provides an example of non-Hermiticity-induced localization.

4.5 pages, 4 figures, 57 references + 5 pages, 4 figures in Appendices

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