Competing topological phases in a non-Hermitian time-reversal symmetry-broken Bernevig-Hughes-Zhang model

• URL: http://arxiv.org/abs/2404.04184v2
• Date: Tue, 17 Sep 2024 17:02:32 GMT
• Title: Competing topological phases in a non-Hermitian time-reversal symmetry-broken Bernevig-Hughes-Zhang model
• Authors: Dipendu Halder, Srijata Lahiri, Saurabh Basu,
• Abstract summary: We show that the inclusion of a spin-dependent non-Hermitian balanced gain/loss potential induces a competition between these first and second-order topological phases. Surprisingly, the previously dormant first-order helical edge states in the nanoribbon resurface as the non-Hermitian effect intensifies.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The Bernevig-Hughes-Zhang (BHZ) model, which serves as a cornerstone in the study of the quantum spin Hall insulators, showcases robust spin-filtered helical edge states in a nanoribbon geometry. In the presence of an in-plane magnetic field, these (first-order) helical states gap out to be replaced by second-order corner states under suitable open-boundary conditions. Here, we show that the inclusion of a spin-dependent non-Hermitian balanced gain/loss potential induces a competition between these first and second-order topological phases. Surprisingly, the previously dormant first-order helical edge states in the nanoribbon resurface as the non-Hermitian effect intensifies, effectively neutralizing the role played by the magnetic field. By employing the projected spin spectra and the spin Chern number, we conclusively explain the resurgence of the first-order topological properties in the time-reversal symmetry-broken BHZ model in presence of non-Hermiticity. Finally, the biorthogonal spin-resolved Berry phase, exhibiting a non-trivial winding, definitively establishes the topological nature of these revived edge states, emphasizing the dominance of non-Hermiticity over the magnetic field.

Related papers

• Topological Order in the Spectral Riemann Surfaces of Non-Hermitian Systems [44.99833362998488]
  We show topologically ordered states in the complex-valued spectra of non-Hermitian systems. These arise when the distinctive exceptional points in the energy surfaces of such models are annihilated. We illustrate the characteristics of the topologically protected states in a non-Hermitian two-band model.
  arXiv  Detail & Related papers  (2024-10-24T10:16:47Z)
• Integrability and dark states of the XX spin-1 central spin model in a transverse field [44.99833362998488]
  The XX central spin model is integrable in the presence of a magnetic field oriented to the XY plane in which the coupling exists. In the spin-1/2 case, it was also shown, through an appropriate limit of the non-skew symmetric XXZ Richardson-Gaudin models, that it remained integrable even when the magnetic field is tilted to contain an in-plane component.
  arXiv  Detail & Related papers  (2024-07-03T11:47:22Z)
• Magnetic field effects on the Kitaev model coupled to environment [0.0]
  An effective non-Hermitian Kitaev model was shown to give rise to a gapless spin liquid state with exceptional points in the Majorana dispersions. We show that the exceptional points remain gapless up to a finite critical magnetic field, in stark contrast to the Hermitian case where an infinitesimal field opens a gap.
  arXiv  Detail & Related papers  (2024-02-08T09:51:37Z)
• Measurement phase transitions in the no-click limit as quantum phase transitions of a non-hermitean vacuum [77.34726150561087]
  We study phase transitions occurring in the stationary state of the dynamics of integrable many-body non-Hermitian Hamiltonians. We observe that the entanglement phase transitions occurring in the stationary state have the same nature as that occurring in the vacuum of the non-hermitian Hamiltonian.
  arXiv  Detail & Related papers  (2023-01-18T09:26:02Z)
• Spin-phonon decoherence in solid-state paramagnetic defects from first principles [79.4957965474334]
  Paramagnetic defects in diamond and hexagonal boron nitride possess a unique combination of spin and optical properties that make them solid-state qubits. Despite the coherence of these spin qubits being critically limited by spin-phonon relaxation, a full understanding of this process is not yet available. We demonstrate that low-frequency two-phonon modulations of the zero-field splitting are responsible for spin relaxation and decoherence.
  arXiv  Detail & Related papers  (2022-12-22T13:48:05Z)
• Fermion production at the boundary of an expanding universe: a cold-atom gravitational analogue [68.8204255655161]
  We study the phenomenon of cosmological particle production of Dirac fermions in a Friedman-Robertson-Walker spacetime. We present a scheme for the quantum simulation of this gravitational analogue by means of ultra-cold atoms in Raman optical lattices.
  arXiv  Detail & Related papers  (2022-12-02T18:28:23Z)
• Ground-state and thermal entanglements in a non-Hermitian XY system with real and imaginary magnetic fields [4.274841694848563]
  We study the non-Hermitian spin-1/2 XY model in the presence of alternating, imaginary and transverse magnetic fields. For the one-dimensional spin chain, the magnetization and entanglement are studied by using the two-spin cluster mean-field approximation.
  arXiv  Detail & Related papers  (2022-03-10T13:45:24Z)
• Gain/loss effects on spin-orbit coupled ultracold atoms in two-dimensional optical lattices [0.5249805590164902]
  We investigate the corresponding non-Hermitian tight-binding model and evaluate the gain/loss effects on various properties of the system. We find that the conventional bulk-boundary correspondence does not break down with only on-site gain/loss due to the lack of non-Hermitian skin effect. Given the technical accessibility of state-dependent atom loss, this model could be realized in current cold-atom experiments.
  arXiv  Detail & Related papers  (2022-01-04T16:00:30Z)
• Phase diagram of a distorted kagome antiferromagnet and application to Y-kapellasite [50.591267188664666]
  We reveal a rich ground state phase diagram even at the classical level. The presented model opens a new direction in the study of kagome antiferromagnets.
  arXiv  Detail & Related papers  (2021-07-28T18:00:03Z)
• Observation of non-Hermitian topology with non-unitary dynamics of solid-state spins [6.692477608972573]
  Non-Hermitian topological phases exhibit a number of exotic features. Non-Hermitian Su-Schrieffer-Heeger (SSH) Hamiltonian is prototypical model for studying non-Hermitian topological phases.
  arXiv  Detail & Related papers  (2020-12-16T19:00:04Z)
• Topological Protection in non-Hermitian Haldane Honeycomb Lattices [0.0]
  Topological phenomena in non-Hermitian systems have recently become a subject of great interest in the photonics and condensed-matter communities. We present the first study on the emergence of topological edge states in two-dimensional Haldane lattices exhibiting balanced gain and loss.
  arXiv  Detail & Related papers  (2020-03-31T17:14:51Z)

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.