Phase transitions and spectral singularities in a class of one-dimensional parity-time-symmetric complex potentials

Fuente: arXiv
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Main Authors: Fan, Jinlin, Wang, Feilong, Zhao, Ruolin Chai Zhibin, Xie, Qiongtao
Format: Preprint
Published: 2025
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author Fan, Jinlin
Wang, Feilong
Zhao, Ruolin Chai Zhibin
Xie, Qiongtao
author_facet Fan, Jinlin
Wang, Feilong
Zhao, Ruolin Chai Zhibin
Xie, Qiongtao
contents We investigate a two-parametric family of one-dimensional non-Hermitian complex potentials with parity-time ($\mathcal{PT}$) symmetry. We find that there exist two distinct types of phase transitions, from an unbroken phase (characterized by a real spectrum) to a broken phase (where the spectrum becomes complex). The first type involves the emergence of a pair of complex eigenvalues bifurcating from the continuous spectrum. The second type is associated with the collision of such pairs at the bottom of the continuous spectrum. The first transition type is closely related to spectral singularities (SSs), at which point the transmission and reflection coefficients are divergent simultaneously. The second is associated with the emergence of bound states. In particular, under specific parameter conditions, we construct an exact bound state solution. By systematically exploring the parameter space, we establish a universal relationship governing the number of SSs in these potentials. These findings provide a fundamental theoretical framework for manipulating wave scattering in non-Hermitian systems, offering promising implications for designing advanced optical and quantum devices.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09010
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Phase transitions and spectral singularities in a class of one-dimensional parity-time-symmetric complex potentials
Fan, Jinlin
Wang, Feilong
Zhao, Ruolin Chai Zhibin
Xie, Qiongtao
Quantum Physics
We investigate a two-parametric family of one-dimensional non-Hermitian complex potentials with parity-time ($\mathcal{PT}$) symmetry. We find that there exist two distinct types of phase transitions, from an unbroken phase (characterized by a real spectrum) to a broken phase (where the spectrum becomes complex). The first type involves the emergence of a pair of complex eigenvalues bifurcating from the continuous spectrum. The second type is associated with the collision of such pairs at the bottom of the continuous spectrum. The first transition type is closely related to spectral singularities (SSs), at which point the transmission and reflection coefficients are divergent simultaneously. The second is associated with the emergence of bound states. In particular, under specific parameter conditions, we construct an exact bound state solution. By systematically exploring the parameter space, we establish a universal relationship governing the number of SSs in these potentials. These findings provide a fundamental theoretical framework for manipulating wave scattering in non-Hermitian systems, offering promising implications for designing advanced optical and quantum devices.
title Phase transitions and spectral singularities in a class of one-dimensional parity-time-symmetric complex potentials
topic Quantum Physics
url https://arxiv.org/abs/2511.09010