Non-Hermitian entanglement dip from scaling-induced exceptional criticality

Fuente: arXiv
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Autores principales: Liu, Sirui, Jiang, Hui, Xue, Wen-Tan, Li, Qingya, Gong, Jiangbin, Liu, Xiaogang, Lee, Ching Hua
Formato: Preprint
Publicado: 2024
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author Liu, Sirui
Jiang, Hui
Xue, Wen-Tan
Li, Qingya
Gong, Jiangbin
Liu, Xiaogang
Lee, Ching Hua
author_facet Liu, Sirui
Jiang, Hui
Xue, Wen-Tan
Li, Qingya
Gong, Jiangbin
Liu, Xiaogang
Lee, Ching Hua
contents It is well established that the entanglement entropy of a critical system generally scales logarithmically with system size. Yet, in this work, we report a new class of non-Hermitian critical transitions that exhibit dramatic divergent dips in their entanglement entropy scaling, strongly violating conventional logarithmic behavior. Dubbed scaling-induced exceptional criticality (SIEC), it transcends existing non-Hermitian mechanisms such as exceptional bound states and non-Hermitian skin effect (NHSE)-induced gap closures, which are nevertheless still governed by logarithmic entanglement scaling. Key to SIEC is its strongly scale-dependent spectrum, where eigenbands exhibit an exceptional crossing only at a particular system size. As such, the critical behavior is dominated by how the generalized Brillouin zone (GBZ) sweeps through the exceptional crossing with increasing system size, and not just by the gap closure per se. We provide a general approach for constructing SIEC systems based on the non-local competition between heterogeneous NHSE pumping directions, and show how a scale-dependent GBZ can be analytically derived to excellent accuracy. Beyond 1D free fermions, SIEC is expected to occur more prevalently in higher-dimensional or even interacting systems, where antagonistic NHSE channels generically proliferate. SIEC-induced entanglement dips generalize straightforwardly to kinks in other entanglement measures such as Renyi entropy, and serve as spectacular demonstrations of how algebraic and geometric singularities in complex band structures manifest in quantum information.
format Preprint
id arxiv_https___arxiv_org_abs_2408_02736
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Non-Hermitian entanglement dip from scaling-induced exceptional criticality
Liu, Sirui
Jiang, Hui
Xue, Wen-Tan
Li, Qingya
Gong, Jiangbin
Liu, Xiaogang
Lee, Ching Hua
Quantum Physics
Mesoscale and Nanoscale Physics
It is well established that the entanglement entropy of a critical system generally scales logarithmically with system size. Yet, in this work, we report a new class of non-Hermitian critical transitions that exhibit dramatic divergent dips in their entanglement entropy scaling, strongly violating conventional logarithmic behavior. Dubbed scaling-induced exceptional criticality (SIEC), it transcends existing non-Hermitian mechanisms such as exceptional bound states and non-Hermitian skin effect (NHSE)-induced gap closures, which are nevertheless still governed by logarithmic entanglement scaling. Key to SIEC is its strongly scale-dependent spectrum, where eigenbands exhibit an exceptional crossing only at a particular system size. As such, the critical behavior is dominated by how the generalized Brillouin zone (GBZ) sweeps through the exceptional crossing with increasing system size, and not just by the gap closure per se. We provide a general approach for constructing SIEC systems based on the non-local competition between heterogeneous NHSE pumping directions, and show how a scale-dependent GBZ can be analytically derived to excellent accuracy. Beyond 1D free fermions, SIEC is expected to occur more prevalently in higher-dimensional or even interacting systems, where antagonistic NHSE channels generically proliferate. SIEC-induced entanglement dips generalize straightforwardly to kinks in other entanglement measures such as Renyi entropy, and serve as spectacular demonstrations of how algebraic and geometric singularities in complex band structures manifest in quantum information.
title Non-Hermitian entanglement dip from scaling-induced exceptional criticality
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2408.02736