Realization and Topological Properties of Third-Order Exceptional Lines Embedded in Exceptional Surfaces

Abstract

As the counterpart of Hermitian nodal structures, the geometry formed by exceptional points (EPs), such as exceptional lines (ELs), entails intriguing spectral topology. We report the experimental realization of order-3 exceptional lines (EL3) that are entirely embedded in order-2 exceptional surfaces (ES2) in a three-dimensional periodic synthetic momentum space. The EL3 and the concomitant ES2, together with the topology of the underlying space, prohibit the evaluation of their topology in the eigenvalue manifold by prevailing topological characterization methods. We resolve this issue by defining a winding number that associates with the resultants of the Hamiltonian. This resultant winding number detects EL3 but ignores the ES2, allowing the diagnosis of the topological currents carried by the EL3, which enables the prediction of their evolution under perturbations. Our results exemplify unprecedented topology of higher-order exceptional geometries and may inspire new non-Hermitian topological applications.

14 pages, 4 figures

References in corpus (10)

• Topological Origin of Non-Hermitian Skin Effects
• Topological nodal line semimetals
• Non-Hermitian Topology and Exceptional-Point Geometries
• Weyl Exceptional Rings in a Three-Dimensional Dissipative Cold Atomic Gas
• Non-Hermitian Morphing of Topological Modes
• Exceptional Non-Abelian Topology in Multiband Non-Hermitian Systems
• Symmetry-protected exceptional and nodal points in non-Hermitian systems
• Non-Hermitian eigenvalue knots and their isotopic equivalence
• Extended topological mode in a one-dimensional non-Hermitian acoustic crystal
• Experimental Realization of Non-Abelian Permutations in a Three-State Non-Hermitian System

Cited by in corpus (15)

• Topological Non-Hermitian skin effect
• Experimental realization of stable exceptional chains protected by non-Hermitian latent symmetries unique to mechanical systems
• Measuring topological invariants for higher-order exceptional points in quantum three-mode systems
• Non-Bloch Theory for Spatiotemporal Photonic Crystals Assisted by Continuum Effective Medium
• Symmetry-driven Phononic Metamaterials
• Topological eigenvalues braiding and quantum state transfer near a third-order exceptional point
• Winding Topology of Multifold Exceptional Points
• Exceptional deficiency of non-Hermitian systems
• Implementation and topological characterization of Weyl exceptional rings in quantum-mechanical systems
• Exceptional Non-Hermitian Topology Associated with Non-Toroidal Brillouin Zones
• An exceptional surface and its topology
• Third-order exceptional surface in a pseudo-Hermitian superconducting circuit
• Non-Hermitian topology in a single driven-dissipative Kerr-Cat qubit
• Higher-order exceptional lines in a non-Hermitian JaynesCummings triangle
• The analytically tractable zoo of similarity-induced exceptional structures