Disorders have a rich influence on topological and localized properties. Here, we explore the effects of different type of disorders (intracell and intercell) on the non-Hermitian system. We first exhibit the phase diagram and find that the intracell disorder and intercell disorder can broaden and narrow the topological region, respectively. Moreover, the skin effect, which is unique in the non-Hermitian system, is broken by disorders. Furthermore, we propose the generalized localization length to settle the issue of how to determine the topological phase boundary explicitly in the disordered non-Hermitian system. Significantly, the rationality of this definition can be verified by similarity transformation, in which we prove that the topological invariant remains invariant. Finally, a byproduct of our definition is that one can analytically get the criticality of topology in the clean-limit non-Hermitian system.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1088/1361-648X/abee3d | DOI Listing |
Entropy (Basel)
January 2025
School of Integrated Circuits, Tsinghua University, Beijing 100084, China.
A notable feature of systems with non-Hermitian skin effects is the sensitivity to boundary conditions. In this work, we introduce one type of boundary condition provided by a coupling impurity. We consider a system where a two-level system as an impurity couples to a nonreciprocal Su-Schrieffer-Heeger chain under periodic boundary conditions at two points with asymmetric couplings.
View Article and Find Full Text PDFEntropy (Basel)
December 2024
Instituto de Física Teórica UAM/CSIC, Campus de Cantoblanco, c/Nicolás Cabrera 13-15, 28049 Madrid, Spain.
Non-Hermitian quantum field theories are a promising tool to study open quantum systems. These theories preserve unitarity if PT symmetry is respected, and in that case, an equivalent Hermitian description exists via the so-called Dyson map. Generically, PT-symmetric non-Hermitian theories can also feature phases where PT symmetry is broken and unitarity is lost.
View Article and Find Full Text PDFNanophotonics
January 2025
Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Topological insulators and bound states in the continuum represent two fascinating topics in the optical and photonic domain. The exploration of their interconnection and potential applications has emerged as a current research focus. Here, we investigated non-Hermitian photonics based on a parallel cascaded-resonator system, where both direct and indirect coupling between adjacent resonators can be independently manipulated.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Theoretical Science, Poornaprajna Institute of Scientific Research, Ranjith Kumar R, Department of Physics, Indian Institute of Technoloby Bombay, Mumbai, 400076, INDIA.
Understanding the critical properties is essential for determining the physical behavior of topological systems. In this context, scaling theories based on the curvature function in momentum space, the renormalization group (RG) method, and the universality of critical exponents have proven effective. In this work, we develop a scaling theory for non-Hermitian topological states of matter.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
School of Physical Sciences, NISER, Jatni, Bhubaneswar, 752050, INDIA.
We study topological charge pumping (TCP) in the Rice-Mele (RM) model with irreciprocal hopping. The non-Hermiticity gives rise to interesting pumping physics, owing to the presence of skin effect and exceptional points. In the static one-dimensional (1D) RM model, we find two independent tuning knobs that can drive the topological transition, namely, non-Hermitian parameter $\gamma$ and system size $N$.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!