Exceptional spectrum and dynamic magnetization

• URL: http://arxiv.org/abs/2103.04109v2
• Date: Tue, 8 Nov 2022 13:13:46 GMT
• Title: Exceptional spectrum and dynamic magnetization
• Authors: Y. B. Shi, K. L. Zhang, Z. Song
• Abstract summary: A macroscopic effect can be induced by a local non-Hermitian term in a many-body system. We show that all single-particle eigenstates coalesce in pairs even only single unidirectional coupling appears. As an application, we study the dynamic magnetization induced by complex fields in an itinerant electron system.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: A macroscopic effect can be induced by a local non-Hermitian term in a many-body system, when it manifests simultaneously level coalescence of a full real degeneracy spectrum, leading to exceptional spectrum. In this paper, we propose a family of systems that support such an intriguing property. It is generally consisted of two arbitrary identical Hermitian sub-lattices in association with unidirectional couplings between them. We show exactly that all single-particle eigenstates coalesce in pairs even only single unidirectional coupling appears. It means that all possible initial states obey the exceptional dynamics, resulting in some macroscopic phenomena, which never appears in a Hermitian system. As an application, we study the dynamic magnetization induced by complex fields in an itinerant electron system. It shows that an initial saturated ferromagnetic state at half-filling can be driven into its opposite state according to the dynamics of high-order exceptional point. Any Hermitian quench term cannot realize a steady opposite saturated ferromagnetic state. Numerical simulations for the dynamical processes of magnetization are performed for several representative situations, including lattice dimensions, global random and local impurity distributions. It shows that the dynamic magnetization processes exhibit universal behavior.

Related papers

• Deep thermalization in continuous-variable quantum systems [2.979579757819132]
  We study the ensemble of pure states supported on a small subsystem of a few modes. We find that the induced ensemble attains a universal form, independent of the choice of measurement basis.
  arXiv  Detail & Related papers  (2024-05-09T00:01:23Z)
• Conventional and unconventional Dicke models: Multistabilities and nonequilibrium dynamics [0.0]
  The stability and dynamics of the system in the thermodynamic limit are examined using a semiclassical approach. We perform small-scale full quantum-mechanical calculations, with results consistent with the semiclassical ones.
  arXiv  Detail & Related papers  (2023-07-11T18:00:12Z)
• Probing dynamics of a two-dimensional dipolar spin ensemble using single qubit sensor [62.997667081978825]
  We experimentally investigate individual spin dynamics in a two-dimensional ensemble of electron spins on the surface of a diamond crystal. We show that this anomalously slow relaxation rate is due to the presence of strong dynamical disorder. Our work paves the way towards microscopic study and control of quantum thermalization in strongly interacting disordered spin ensembles.
  arXiv  Detail & Related papers  (2022-07-21T18:00:17Z)
• Spreading of a local excitation in a Quantum Hierarchical Model [62.997667081978825]
  We study the dynamics of the quantum Dyson hierarchical model in its paramagnetic phase. An initial state made by a local excitation of the paramagnetic ground state is considered. A localization mechanism is found and the excitation remains close to its initial position at arbitrary times.
  arXiv  Detail & Related papers  (2022-07-14T10:05:20Z)
• Formation of robust bound states of interacting microwave photons [148.37607455646454]
  One of the hallmarks of interacting systems is the formation of multi-particle bound states. We develop a high fidelity parameterizable fSim gate that implements the periodic quantum circuit of the spin-1/2 XXZ model. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons.
  arXiv  Detail & Related papers  (2022-06-10T17:52:29Z)
• Distinct universality classes of diffusive transport from full counting statistics [0.4014524824655105]
  We study the full counting statistics of spin transport in various integrable and non-integrable anisotropic one-dimensional spin models. We find that spin transport, while diffusive on average, is governed by a distinct non-Gaussian universality class. Our predictions can directly be tested in experiments using quantum gas microscopes or superconducting qubit arrays.
  arXiv  Detail & Related papers  (2022-03-17T18:00:01Z)
• Understanding the propagation of excitations in quantum spin chains with different kind of interactions [68.8204255655161]
  It is shown that the inhomogeneous chains are able to transfer excitations with near perfect fidelity. It is shown that both designed chains have in common a partially ordered spectrum and well localized eigenvectors.
  arXiv  Detail & Related papers  (2021-12-31T15:09:48Z)
• Dispersive readout of molecular spin qudits [68.8204255655161]
  We study the physics of a magnetic molecule described by a "giant" spin with multiple $d > 2$ spin states. We derive an expression for the output modes in the dispersive regime of operation. We find that the measurement of the cavity transmission allows to uniquely determine the spin state of the qudits.
  arXiv  Detail & Related papers  (2021-09-29T18:00:09Z)
• Bell-state generation for spin qubits via dissipative coupling [3.011018394325566]
  We investigate the dynamics of two spin qubits interacting with a magnetic medium. We show how a sizable long-lived entanglement can be established via the magnetic environment. Our study may find applications in quantum information science, quantum spintronics, and for sensing of nonlocal quantum correlations.
  arXiv  Detail & Related papers  (2021-08-16T22:36:48Z)
• Observation of Time-Crystalline Eigenstate Order on a Quantum Processor [80.17270167652622]
  Quantum-body systems display rich phase structure in their low-temperature equilibrium states. We experimentally observe an eigenstate-ordered DTC on superconducting qubits. Results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors.
  arXiv  Detail & Related papers  (2021-07-28T18:00:03Z)
• Dynamic magnetization in non-Hermitian quantum spin system [0.0]
  High-order exceptional point up to ($N+1)-level coalescence is created at the critical local complex field applied to the $N$-size quantum spin chain. Our findings highlight the cooperation of non-Hermiticity and the interaction in quantum spin system.
  arXiv  Detail & Related papers  (2020-06-02T00:41:45Z)

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.