Observation of dynamical degeneracy splitting for the non-Hermitian skin effect

Abstract

The non-Hermitian skin effect is a distinctive phenomenon in non-Hermitian systems, which manifests as the anomalous localization of bulk states at the boundary. To understand the physical origin of the non-Hermitian skin effect, a bulk band characterization based on the dynamical degeneracy on an equal frequency contour is proposed, which reflects the strong anisotropy of the spectral function. In this paper, we report the experimental observation of both phenomena in a two-dimensional acoustic crystal, and reveal their remarkable correspondence by performing single-frequency excitation measurements. Our work not only provides a controllable experimental platform for studying the non-Hermitian physics, but also confirms the correspondence between the non-Hermitian skin effect and the dynamical degeneracy splitting, paving a new way to characterize the non-Hermitian skin effect.

14+3 pages, 4+4 figures

References in corpus (22)

• Topological Origin of Non-Hermitian Skin Effects
• $(d-2)$-dimensional edge states of rotation symmetry protected topological states
• Efficient Light Funneling based on the non-Hermitian Skin Effect
• Non-Hermitian Topology and Exceptional-Point Geometries
• Universal non-Hermitian skin effect in two and higher dimensions
• Observation of the exceptional point in cavity magnon-polaritons
• Observation of Non-Hermitian Skin Effect and Topology in Ultracold Atoms
• Observation of hybrid higher-order skin-topological effect in non-Hermitian topolectrical circuits
• Higher-order non-Hermitian skin effect
• Acoustic non-Hermitian skin effect from twisted winding topology
• Observation of higher-order non-Hermitian skin effect
• Non-Hermitian Morphing of Topological Modes
• Non-Hermitian route to higher-order topology in an acoustic crystal
• Transient non-Hermitian skin effect
• Observation of Acoustic Non-Hermitian Bloch Braids and Associated Topological Phase Transitions
• Experimental Realization of Weyl Exceptional Rings in a Synthetic Three-Dimensional Non-Hermitian Phononic Crystal
• Anomalous single-mode lasing induced by nonlinearity and the non-Hermitian skin effect
• Experimental Observation of Efficient Nonreciprocal Mode Transitions via Spatiotemporally-Modulated Acoustic Metamaterials
• Topological Modes in a Laser Cavity through Exceptional State Transfer
• Experimental Realization of Geometry-Dependent Skin Effect in a Reciprocal Two-Dimensional Lattice
• Direct Measurement of Topological Properties of an Exceptional Parabola
• Dynamical Degeneracy Splitting and Directional Invisibility in Non-Hermitian Systems

Cited by in corpus (16)

• Two-dimensional non-Hermitian skin effect in an ultracold Fermi gas
• Experimental Realization of Geometry-Dependent Skin Effect in a Reciprocal Two-Dimensional Lattice
• Topological origin of non-Hermitian skin effect in higher dimensions and uniform spectra
• Edge theory of non-Hermitian skin modes in higher dimensions
• A brief review of hybrid skin-topological effect
• Algebraic non-Hermitian skin effect and generalized Fermi surface formula in arbitrary dimensions
• Universal spectral moment theorem and its applications in non-Hermitian systems
• Tailoring Bound State Geometry in High-Dimensional Non-Hermitian Systems
• Implementing non-Abelian Hatano-Nelson model in electric circuits
• Non-Bloch Dirac Points and Phase Diagram in the Stacked Non-Hermitian SSH Model
• Nonlinear Hall effects with an exceptional ring
• Non-Hermitian reshaping of high-order Landau modes
• Experimentally Probing Non-Hermitian Spectral Transition and Eigenstate Skewness
• Anatomy of Higher-Order Non-Hermitian Skin and Boundary Modes
• Algebraic skin effect in two-dimensional non-Hermitian metamaterials
• Algebraic States in Continuum in $d>1$ Dimensional Non-Hermitian Systems