Imaginary-Stark skin effect

A unique phenomenon in non-Hermitian systems is the non-Hermitian skin effect (NHSE), namely, the boundary localization of continuous-spectrum eigenstates. However, studies on the NHSE in systems without translational invariance are still limited. Here, we unveil a new class of NHSE, dubbed the imag...

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Bibliographic Details
Main Authors: Heng Lin, Jinghui Pi, Yunyao Qi, Wei Qin, Franco Nori, Gui-Lu Long
Format: Article
Language:English
Published: American Physical Society 2025-08-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/xc42-7hcg
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Summary:A unique phenomenon in non-Hermitian systems is the non-Hermitian skin effect (NHSE), namely, the boundary localization of continuous-spectrum eigenstates. However, studies on the NHSE in systems without translational invariance are still limited. Here, we unveil a new class of NHSE, dubbed the imaginary-Stark skin effect (ISSE), in a one-dimensional lossy lattice with a spatially increasing loss rate. This ISSE is beyond the framework of non-Bloch band theory and exhibits intriguing properties significantly different from the conventional NHSE. Specifically, the energy spectrum of our model has a T-shaped feature, with approximately half of the eigenstates localized at the left boundary. Furthermore, each skin mode can be expressed as a single stable, exponentially decaying wave within the bulk region. Such peculiar behaviors are analyzed via the transfer-matrix method, whose eigendecomposition quantifies the formation of the ISSE. Our work provides new insights into the NHSE in systems without translational symmetry and contributes to the understanding of non-Hermitian systems.
ISSN:2643-1564