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|
Identifier |
000451832 |
Title |
Non-Hermitian jumps in disordered lattices |
Alternative Title |
Μη-Ερμιτιανά άλματα σε τυχαία πλέγματα |
Author
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Λεβέντης, Ανδρόνικος Α.
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Thesis advisor
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Μακρής, Κωνσταντίνος
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Reviewer
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Οικονόμου, Ελευθέριος
Ζώτος, Ξενοφών
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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.
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Language |
English |
Subject |
Anderson localization |
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Non-Hermitian physics |
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Photonics |
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Εντοπισμός Άντερσον |
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Μη-Ερμιτιανή φυσική |
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Φωτονική |
Issue date |
2022-11-25 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/b/0/c/metadata-dlib-1666777906-407045-9043.tkl
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Views |
505 |