Spectral and Entanglement Transitions from Non-Hermitian Skin Pumping

Fuente: arXiv
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Autore principale: Li, Qingya
Natura: Preprint
Pubblicazione: 2025
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author Li, Qingya
author_facet Li, Qingya
contents Non-Hermitian physics has unveiled unconventional spectral, topological and critical phenomena, challenging traditional band theories. This thesis advances its understanding in three aspects. First, the non-Hermitian skin effect (NHSE) is shown to protect real spectra in some ansatz models, not relying on crystal symmetries. Second, we discover the phenomenon of scaling-induced non-Hermitian exceptional criticality (SIEC), marked by a unconventional negative dip in entanglement entropy scaling, deviating from the well-established logarithmic behavior. A scaling-dependent generalized Brillouin zone (GBZ) is developed to analytically predict this SIEC. Third, we formulate a theoretical framework for phase-space GBZs, extending the concept of the GBZ to position-dependent systems, particularly for those with spatially inhomogeneous NHSE hoppings. Unprecedented phenomena, including GBZ bifurcation which also protects the stability of real spectra, are revealed, introducing new forms of topological robustness governed by phase-space GBZ bifurcations. This thesis also explores the NHSE in Bethe lattices, where the hyperbolic-like lattice geometry gives rise to a hierarchy of loop sizes that leads to new forms of critical NHSE behavior.
format Preprint
id arxiv_https___arxiv_org_abs_2502_12041
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectral and Entanglement Transitions from Non-Hermitian Skin Pumping
Li, Qingya
Mesoscale and Nanoscale Physics
Non-Hermitian physics has unveiled unconventional spectral, topological and critical phenomena, challenging traditional band theories. This thesis advances its understanding in three aspects. First, the non-Hermitian skin effect (NHSE) is shown to protect real spectra in some ansatz models, not relying on crystal symmetries. Second, we discover the phenomenon of scaling-induced non-Hermitian exceptional criticality (SIEC), marked by a unconventional negative dip in entanglement entropy scaling, deviating from the well-established logarithmic behavior. A scaling-dependent generalized Brillouin zone (GBZ) is developed to analytically predict this SIEC. Third, we formulate a theoretical framework for phase-space GBZs, extending the concept of the GBZ to position-dependent systems, particularly for those with spatially inhomogeneous NHSE hoppings. Unprecedented phenomena, including GBZ bifurcation which also protects the stability of real spectra, are revealed, introducing new forms of topological robustness governed by phase-space GBZ bifurcations. This thesis also explores the NHSE in Bethe lattices, where the hyperbolic-like lattice geometry gives rise to a hierarchy of loop sizes that leads to new forms of critical NHSE behavior.
title Spectral and Entanglement Transitions from Non-Hermitian Skin Pumping
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2502.12041