Observation of higher-order non-Hermitian skin effect

Abstract

Hermitian theories play a major role in understanding the physics of most phenomena. It has been found only in the past decade that non-Hermiticity enables unprecedented effects such as exceptional points, spectral singularities and bulk Fermi arcs. Recent studies further show that non-Hermiticity can fundamentally change the topological band theory, leading to the non-Hermitian band topology and non-Hermitian skin effect, as confirmed in one-dimensional (1D) systems. However, in higher dimensions, these non-Hermitian effects remain unexplored in experiments. Here, we demonstrate the spin-polarized, higher-order non-Hermitian skin effect in two-dimensional (2D) acoustic metamaterials. Using a lattice of coupled whisper-gallery acoustic resonators, we realize a spinful 2D higher-order topological insulator (HOTI) where the spin-up and spin-down states are emulated by the anti-clockwise and clockwise modes, respectively. We find that the non-Hermiticity drives wave localizations toward opposite edge boundaries depending on the spin polarizations. More interestingly, for finite systems with both edge and corner boundaries, the higher-order non-Hermitian skin effect leads to wave localizations toward two corner boundaries for the bulk, edge and corner states in a spin-dependent manner. We further show that such a non-Hermitian skin effect enables rich wave manipulation through the loss configuration in each unit-cell. The reported spin-dependent, higher-order non-Hermitian skin effect reveals the interplay between higher-order topology and non-Hermiticity, which is further enriched by the spin degrees of freedom. This unveils a new horizon in the study of non-Hermitian physics and the design of non-Hermitian metamaterials.

References in corpus (8)

• Topological Origin of Non-Hermitian Skin Effects
• Visualization of Branch Points in PT-Symmetric Waveguides
• Higher-order topological insulators and semimetals on the breathing Kagome and pyrochlore lattices
• Efficient Light Funneling based on the non-Hermitian Skin Effect
• Visualization of higher-order topological insulating phases in two-dimensional dielectric photonic crystals
• Universal non-Hermitian skin effect in two and higher dimensions
• Higher-order non-Hermitian skin effect
• PT-symmetric quantum mechanics

Cited by in corpus (138)

• Non-Hermitian Topology and Exceptional-Point Geometries
• Topological acoustics
• Topological Non-Hermitian skin effect
• Entanglement Phase Transition Induced by the Non-Hermitian Skin Effect
• Transient non-Hermitian skin effect
• Controlling mass and energy diffusion with metamaterials
• Observation of exceptional points and skin effect correspondence in non-Hermitian phononic crystals
• Many-body topology of non-Hermitian systems
• Hybrid skin-topological modes without asymmetric couplings
• Anomalous single-mode lasing induced by nonlinearity and the non-Hermitian skin effect
• Two-dimensional non-Hermitian skin effect in an ultracold Fermi gas
• Experimental identification of the second-order non-Hermitian skin effect with physics-graph-informed machine learning
• Anomalous Floquet non-Hermitian skin effect in a ring resonator lattice
• Fate of the non-Hermitian skin effect in many-body fermionic systems
• Enhancement of Second-Order Non-Hermitian Skin Effect by Magnetic Fields
• Non-Hermitian Topological Phases: Principles and Prospects
• Non-Hermitian Photonic Lattices: tutorial
• Non-Bloch bands in two-dimensional non-Hermitian systems
• Non-Hermitian waves in a continuous periodic model and application to photonic crystals
• Non-Hermitian Floquet Topological Matter -- A Review
• Observation of dynamical degeneracy splitting for the non-Hermitian skin effect
• Non-Hermitian Chiral Skin Effect
• Photonic corner skin modes
• Observation of non-Hermitian topology in a multi-terminal quantum Hall device
• Bulk-Bulk Correspondence in Disordered Non-Hermitian Systems
• Topological origin of non-Hermitian skin effect in higher dimensions and uniform spectra
• Loss-induced Floquet non-Hermitian skin effect
• Experimental observation of non-Hermitian higher-order skin interface states in topological electric circuits
• Biorthogonal Dynamical Quantum Phase Transitions in Non-Hermitian Systems
• Quantum Entanglement of Non-Hermitian Quasicrystals
• Theoretical Prediction of Non-Hermitian Skin Effect in Ultracold Atom Systems
• Hybrid skin-topological effect induced by eight-site cells and arbitrary adjustment of the localization of topological edge states
• Non-Hermitian skin effect in one-dimensional interacting Bose gas
• Bulk-boundary correspondence in point-gap topological phases
• Spectral Properties of Disordered Interacting Non-Hermitian Systems
• Synthetic non-Abelian gauge fields for non-Hermitian systems
• Many-Body Non-Hermitian Skin Effect for Multipoles
• Topological energy braiding of the non-Bloch bands
• Occupation-dependent particle separation in one-dimensional non-Hermitian lattices
• Hybrid higher-order skin-topological effect in hyperbolic lattices
• Manipulating non-reciprocity in a two-dimensional magnetic quantum walk
• Universal platform of point-gap topological phases from topological materials
• Continuum of Bound States in a Non-Hermitian Model
• Amplification of quantum signals by the non-Hermitian skin effect
• A Non-Hermitian Moiré Valley Filter
• Generalized bulk-boundary correspondence in periodically driven non-Hermitian systems
• Erratic non-Hermitian skin localization
• Percolation-induced PT symmetry breaking
• Edge theory of non-Hermitian skin modes in higher dimensions
• Non-Hermitian skin effect induced by Rashba-Dresselhaus spin-orbit coupling
• Phase transitions and bunching of correlated particles in a non-Hermitian quasicrystal
• Non-Hermitian Topology in Hermitian Topological Matter
• Self acceleration from spectral geometry in dissipative quantum-walk dynamics
• Experimental realization of stable exceptional chains protected by non-Hermitian latent symmetries unique to mechanical systems
• Hybrid scale-free skin effect in non-Hermitian systems: A transfer matrix approach
• Non-Hermitian Second-Order Topological Phases and Bipolar Skin Effect in Photonic Kagome Crystals
• Modified Generalized-Brillouin-Zone Theory with On-site Disorders
• Evidencing non-Bloch dynamics in temporal topolectrical circuits
• Quantum criticality in interacting bosonic Kitaev-Hubbard models
• Exact Solutions Disentangle Higher-Order Topology in 2D Non-Hermitian Lattices
• Non-Hermiticity induced Exceptional Points and Skin Effect in the Dice-Haldane Model
• Algebraic non-Hermitian skin effect and generalized Fermi surface formula in arbitrary dimensions
• Non-Hermitian second-order topological superconductors
• Non-Hermitian topological ohmmeter
• Quantum Metric Unveils Defect Freezing in Non-Hermitian Systems
• Robust zero modes in non-Hermitian systems without global symmetries
• Quantum entanglement and non-Hermiticity in free-fermion systems
• Quantum walks of correlated photons in non-Hermitian photonic lattices
• Exponentially Enhanced non-Hermitian Cooling
• Spectral structure and doublon dissociation in the two-particle non-Hermitian Hubbard model
• Emerging exceptional point with breakdown of skin effect in non-Hermitian systems
• Pseudomagnetic suppression of non-Hermitian skin effect
• Observables in non-Hermitian systems: A methodological comparison
• Higher-order Skin Effect through a Hermitian-non-Hermitian Correspondence and Its Observation in an Acoustic Kagome Lattice
• Non-Markovian skin effect
• Hopf Bifurcation of Nonlinear Non-Hermitian Skin Effect
• Selective and tunable excitation of topological non-Hermitian skin modes
• Multifractality of many-body non-Hermitian skin effect
• Acoustic circular dichroism in a three-dimensional chiral metamaterial
• Non-Hermitian boost deformation
• Topological $n$-root Su-Schrieffer-Heeger model in a non-Hermitian photonic ring system
• Generalized Lieb's theorem for noninteracting non-Hermitian $n$-partite tight-binding lattices
• Selectable diffusion direction with topologically protected edge modes
• Non-Hermitian Skin Effect Along Hyperbolic Geodesics
• Concentrated subradiant modes in one-dimensional atomic array coupled with chiral waveguides
• Intrinsic-perturbation induced anomalous higher-order boundary states in non-Hermitian systems
• General theory for infernal points in non-Hermitian systems
• Implementing non-Abelian Hatano-Nelson model in electric circuits
• Dissipative two-dimensional Raman lattice
• Anisotropic-scaling localization in higher-dimensional non-Hermitian systems
• Multiple topological transitions and spectral singularities in non-Hermitian Floquet systems
• Inner non-Hermitian skin effect on Bethe lattice
• Dissipation Enhanced Unidirectional Transport in Topological Systems
• Measuring Non-Hermitian Topological Invariants Directly from Quench Dynamics
• Restoration of non-Hermitian bulk-boundary correspondence by counterbalancing skin effect
• Optical pumping through the Liouvillian skin effect
• Topologically compatible non-Hermitian skin effect
• Symmetry-driven Phononic Metamaterials
• Super-enhanced Sensitivity in Non-Hermitian Systems at Infernal Points
• Boundary-driven many-body phase transitions in a non-Hermitian disordered fermionic chain
• Manipulating Spectral Windings and Skin Modes through Nonconservative Couplings
• Bulk-boundary correspondence in topological systems with the momentum dependent energy shift
• Fate of localization features in a one-dimensional non-Hermitian flat-band lattice with quasiperiodic modulations
• Dual Symmetry Classification of Non-Hermitian Systems and ${\mathbb{Z}}_2$ Point-Gap Topology of a Non-Unitary Quantum Walk
• Non-Hermitian ultra-strong bosonic clustering through interaction-induced caging
• Nonreciprocal amplification toward chaos in a chain of Duffing oscillators
• Optical non-Hermitian skin effect in two-dimensional uniform media
• Antichiral and trap-skin dynamics in a nonreciprocal bosonic two-leg ladder with artificial magnetic flux
• Non-Hermitian ${\mathbb{Z}}_4$ skin effect protected by glide symmetry
• Non-Hermitian systems with a real spectrum and selective skin effect
• Non-Hermitian reshaping of high-order Landau modes
• Fragmented exceptional points and their bulk and edge realizations in lattice models
• Defect-driven incoherent skin localization
• Anderson-skin dualism: A boundary-dependent effect in non-Hermitian disordered coupled systems
• Meissner effect in non-Hermitian superconductors
• Topological and fractal defect states in non-Hermitian lattices
• Concurrent Skin-scale-free Localization and Criticality under Möbius Boundary Conditions in a Non-Hermitian Ladder
• Laser induced $\mathcal{P}\mathcal{T}$-symmetry breaking in the fluctuations of electronic fluids
• A non-Hermitian Su-Schrieffer-Heeger model with the energy levels of free parafermions
• Non-Hermitian Hopf insulators
• Multifractal statistics of non-Hermitian skin effect on the Cayley tree
• Exceptionally deficient topological square-root insulators
• Non-Hermitian topology of transport in the quantum Hall phases in graphene
• Hybrid Higher-Order Skin Topological Modes in the Two-Dimensional Su-Schrieffer-Heeger Model with Nonreciprocal Hoppings
• Disorder-driven exceptional points and concurrent topological phase transitions in non-Hermitian systems
• Infinite-component $BF$ field theory: Connection of fracton order, Toeplitz braiding, and non-Hermitian amplification
• Adiabatic charge transport through non-Bloch bands
• Magnetic Control of the Non-Hermitian Skin Effect in Two-Dimensional Lattices
• Critical properties in the non-Hermitian Aubry-Andre-Stark model
• Interplay of Disorder and Point-Gap Topology: Chiral Modes, Localization and Non-Hermitian Anderson Skin Effect in One Dimension
• Tailoring Corner States and Exceptional Points in Altermagnets
• Unified Multipole Bott Indices for Non-Hermitian Skin Effect in Different Orders
• Quasiperiodic Skin Criticality in an Exactly Solvable Non-Hermitian Quasicrystal
• Wiener-Hopf factorization and non-Hermitian topology for Amoeba formulation in one-dimensional multiband systems
• Observation of non-Hermitian point gap in photonic crystals
• Floquet spin textures in optically pumped non-Hermitian surface states
• Exceptional horns in $n$-root graphene and Lieb photonic ring lattices
• Liouvillian skin effects in two-dimensional electron systems at finite temperatures