Non-Hermitian extended midgap states and bound states in the continuum

• URL: http://arxiv.org/abs/2310.18270v2
• Date: Fri, 26 Jan 2024 13:01:02 GMT
• Title: Non-Hermitian extended midgap states and bound states in the continuum
• Authors: Maria Zelenayova, Emil J. Bergholtz
• Abstract summary: We find two flavours of bound states in the continuum, both stable even in the absence of chiral symmetry. Results clarify fundamental aspects of topology, and symmetry in the light of different approaches to the anomalous non-Hermitan bulk-boundary correspondence.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: We investigate anomalous localization phenomena in non-Hermitian systems by solving a class of generalized Su-Schrieffer-Heeger/Rice-Mele models and by relating their provenance to fundamental notions of topology, symmetry-breaking and biorthogonality. We find two flavours of bound states in the continuum, both stable even in the absence of chiral symmetry. The first being skin bulk states which are protected by the spectral winding number. The second flavour is constituted by boundary modes associated with a quantized biorthogonal polarization. Furthermore, we find the extended state stemming from the boundary state that delocalizes while remaining in the gap at bulk critical points. This state may also delocalize within a continuum of localized (skin) states. These results clarify fundamental aspects of topology, and symmetry in the light of different approaches to the anomalous non-Hermitan bulk-boundary correspondence -- and are of direct experimental relevance for mechanical, electrical and photonic systems.

Related papers

• Exotic localization for the two body bound states in the non-reciprocal Hubbard model [9.166422816832855]
  We investigate the localization behavior of two-body Hubbard model in the presence of non-reciprocal tunneling. We present the non-Hermitian bound states obtained with the center of mass methods in the conditions of strong repulsive interaction.
  arXiv  Detail & Related papers  (2024-09-12T09:43:33Z)
• Dissipative Boundary State Preparation [3.0574700762497744]
  We devise a generic and experimentally accessible recipe to prepare boundary states of topological or nontopological quantum systems. We harness the spatial structure of boundary states which vanish on sublattices where losses are suitably engineered. This yields unique nontrivial steady states that populate the targeted boundary states with infinite lifetimes while all other states are exponentially damped in time.
  arXiv  Detail & Related papers  (2023-04-28T18:10:12Z)
• Entanglement and localization in long-range quadratic Lindbladians [49.1574468325115]
  Signatures of localization have been observed in condensed matter and cold atomic systems. We propose a model of one-dimensional chain of non-interacting, spinless fermions coupled to a local ensemble of baths. We show that the steady state of the system undergoes a localization entanglement phase transition by tuning $p$ which remains stable in the presence of coherent hopping.
  arXiv  Detail & Related papers  (2023-03-13T12:45:25Z)
• Localization control born of intertwined quasiperiodicity and non-Hermiticity [0.0]
  We show for the first time that the intertwined quasiperiodicity and non-Hermiticity can give rise to striking effects. In particular, we explore the wave function localization character in the Aubry-Andre-Fibonacci (AAF) model.
  arXiv  Detail & Related papers  (2022-11-25T19:00:05Z)
• Topologically bound states, non-Hermitian skin effect and flat bands, induced by two-particle interaction [91.3755431537592]
  We study theoretically repelling quantum states of two spinless particles in a one-dimensional tight-binding model. We demonstrate, that when the particles are not identical, their interaction drives nontrivial correlated two-particle states.
  arXiv  Detail & Related papers  (2022-11-11T07:34:54Z)
• Giant atom induced zero modes and localization in the nonreciprocal Su-Schrieffer-Heeger chai [2.105031112138881]
  A giant atom couples to a nonreciprocal SuSchrieffer-Heeger chain at two points and plays the role of defects. We study the spectrum and localization of eigenstates of the system and find that the giant atom can induce asymmetric zero modes.
  arXiv  Detail & Related papers  (2022-11-03T13:57:16Z)
• Detecting bulk and edge exceptional points in non-Hermitian systems through generalized Petermann factors [7.371841894852217]
  Non-orthogonality in non-Hermitian quantum systems gives rise to tremendous exotic quantum phenomena. We introduce an interesting quantity (denoted as $eta$) as a new variant of the Petermann factor to measure non-unitarity.
  arXiv  Detail & Related papers  (2022-08-31T16:24:03Z)
• Role of boundary conditions in the full counting statistics of topological defects after crossing a continuous phase transition [62.997667081978825]
  We analyze the role of boundary conditions in the statistics of topological defects. We show that for fast and moderate quenches, the cumulants of the kink number distribution present a universal scaling with the quench rate.
  arXiv  Detail & Related papers  (2022-07-08T09:55:05Z)
• Spectrum of localized states in fermionic chains with defect and adiabatic charge pumping [68.8204255655161]
  We study the localized states of a generic quadratic fermionic chain with finite-range couplings. We analyze the robustness of the connection between bands against perturbations of the Hamiltonian.
  arXiv  Detail & Related papers  (2021-07-20T18:44:06Z)
• Non-equilibrium stationary states of quantum non-Hermitian lattice models [68.8204255655161]
  We show how generic non-Hermitian tight-binding lattice models can be realized in an unconditional, quantum-mechanically consistent manner. We focus on the quantum steady states of such models for both fermionic and bosonic systems.
  arXiv  Detail & Related papers  (2021-03-02T18:56:44Z)
• Observing localisation in a 2D quasicrystalline optical lattice [52.77024349608834]
  We experimentally and numerically study the ground state of non- and weakly-interacting bosons in an eightfold symmetric optical lattice. We find extended states for weak lattices but observe a localisation transition at a lattice depth of $V_0.78(2),E_mathrmrec$ for the non-interacting system.
  arXiv  Detail & Related papers  (2020-01-29T15:54:42Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.