It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead...It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead to the suppression of the non-Hermitian skin effect. With an increasing pseudomagnetic field, the skin modes are found to be pushed into the bulk, accompanied by the reduction of skin topological area and the restoration of Landau level energies. Our results provide a time-reversal invariant route to localization control and could be useful in various classical wave devices that are able to host the non-Hermitian skin effect but inert to magnetic fields.展开更多
The interaction of band topology and disorder can give rise to intriguing phenomena.One paradigmatic example is the topological Anderson insulator,whose nontrivial topology is induced in a trivial system by disorders....The interaction of band topology and disorder can give rise to intriguing phenomena.One paradigmatic example is the topological Anderson insulator,whose nontrivial topology is induced in a trivial system by disorders.In this study,we investigate the efect of purely non-Hermitian disorders on topological systems using a one-dimensional acoustic lattice with coupled resonators.Specifically,we construct a theoretical framework to describe the non-Hermitian topological Anderson insulator phase solely driven by disordered loss modulation.Then,the complete evolution of non-Hermitian disorder-induced topological phase transitions,from an initial trivial phase to a topological Anderson phase and finally to a trivial Anderson phase,is revealed experimentally using both bulk and edge spectra.Interestingly,topological modes induced by non-Hermitian disorders to be immune to both weak Hermitian and non-Hermitian disorders.These findings pave the way for future research on disordered non-Hermitian systems for novel wave manipulation.展开更多
The current understanding of topological insulators and their classical wave analogs,such as photonic topological insulators,is mainly based on topological band theory.However,standard band theory does not apply to am...The current understanding of topological insulators and their classical wave analogs,such as photonic topological insulators,is mainly based on topological band theory.However,standard band theory does not apply to amorphous phases of matter,which are formed by non-crystalline lattices with no long-range positional order but only shortrange order,exhibiting unique phenomena such as the glass-to-liquid transition.Here,we experimentally investigate amorphous variants of a Chern number-based photonic topological insulator.By tuning the disorder strength in the lattice,we demonstrate that photonic topological edge states can persist into the amorphous regime prior to the glass-to-liquid transition.After the transition to a liquid-like lattice configuration,the signatures of topological edge states disappear.This interplay between topology and short-range order in amorphous lattices paves the way for new classes of non-crystalline topological photonic bandgap materials.展开更多
基金supported by National Research Foundation Singapore Competitive Research Program (NRF-CRP232019-0007)support from the start-up fund and the direct grant (4053675) of The Chinese University of Hong Kong。
文摘It has recently been shown that the non-Hermitian skin effect can be suppressed by magnetic fields. In this work, using a two-dimensional tight-binding lattice, we demonstrate that a pseudomagnetic field can also lead to the suppression of the non-Hermitian skin effect. With an increasing pseudomagnetic field, the skin modes are found to be pushed into the bulk, accompanied by the reduction of skin topological area and the restoration of Landau level energies. Our results provide a time-reversal invariant route to localization control and could be useful in various classical wave devices that are able to host the non-Hermitian skin effect but inert to magnetic fields.
基金supported by the National Key Research&Development Program of China(Grant Nos.2022YFA1404400,and 2022YFA1404403)the National Natural Science Foundation of China(Grant No.92263208)the Fundamental Research Funds for the Central Universities。
文摘The interaction of band topology and disorder can give rise to intriguing phenomena.One paradigmatic example is the topological Anderson insulator,whose nontrivial topology is induced in a trivial system by disorders.In this study,we investigate the efect of purely non-Hermitian disorders on topological systems using a one-dimensional acoustic lattice with coupled resonators.Specifically,we construct a theoretical framework to describe the non-Hermitian topological Anderson insulator phase solely driven by disordered loss modulation.Then,the complete evolution of non-Hermitian disorder-induced topological phase transitions,from an initial trivial phase to a topological Anderson phase and finally to a trivial Anderson phase,is revealed experimentally using both bulk and edge spectra.Interestingly,topological modes induced by non-Hermitian disorders to be immune to both weak Hermitian and non-Hermitian disorders.These findings pave the way for future research on disordered non-Hermitian systems for novel wave manipulation.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFB1200100)the program of the China Scholarships Council(No.201806075001)sponsored by Singapore MOE Academic Research Fund Tier 3 Grant MOE2016-T3-1-006,Tier 1 Grants RG187/18 and RG174/16(S),and Tier 2 Grant MOE 2018-T2-1-022(S).
文摘The current understanding of topological insulators and their classical wave analogs,such as photonic topological insulators,is mainly based on topological band theory.However,standard band theory does not apply to amorphous phases of matter,which are formed by non-crystalline lattices with no long-range positional order but only shortrange order,exhibiting unique phenomena such as the glass-to-liquid transition.Here,we experimentally investigate amorphous variants of a Chern number-based photonic topological insulator.By tuning the disorder strength in the lattice,we demonstrate that photonic topological edge states can persist into the amorphous regime prior to the glass-to-liquid transition.After the transition to a liquid-like lattice configuration,the signatures of topological edge states disappear.This interplay between topology and short-range order in amorphous lattices paves the way for new classes of non-crystalline topological photonic bandgap materials.
