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Identifier

000451832

Title

Non-Hermitian jumps in disordered lattices

Alternative Title

Μη-Ερμιτιανά άλματα σε τυχαία πλέγματα

Author

Λεβέντης, Ανδρόνικος Α.

Thesis advisor

Μακρής, Κωνσταντίνος

Reviewer

Οικονόμου, Ελευθέριος
Ζώτος, Ξενοφών

Abstract

The subject of this thesis is to study the appearance of a new and unexpected form of wave propagation that appears in the dynamics of certain non-Hermitian random lattices, namely ”delocalization via jumps”, wherein the normalized field profile of the evolution of an initial excitation exhibits a counterintuitive propagation mechanism via quantized jumps despite the strong disorder induced localization of the eigenstates of the lattice. The dynamics of such systems is explored and the physical mechanism behind such an effect is elucidated in the context of non- Hermitian Anderson localization. This work initially focuses in one-dimensional chains of evanescently coupled waveguides exhibiting randomly distributed gain or loss, and then shifts its focus to arrays of non-reciprocally coupled waveguides described by the Hatano-Nelson model. The origin of the non-Hermitian jumps that are exhibited by such systems for certain types of disorder is then uncovered by examining their relevant spectral properties that arise from their non-Hermiticity, such as the non-orthogonality of their eigenstates. Finally, the impact of the non- Hermitian skin effect (NHSE) on the jumpy dynamics as well as a generalization of our results for in two-dimensional tight-binding lattices are also presented.

Language

English

Subject

Anderson localization

Non-Hermitian physics

Photonics

Εντοπισμός Άντερσον

Μη-Ερμιτιανή φυσική

Φωτονική

Issue date

2022-11-25

Collection