Quantum correlations versus spin magnitude: Transition to the classical limit

• URL: http://arxiv.org/abs/2506.04782v1
• Date: Thu, 05 Jun 2025 09:11:22 GMT
• Title: Quantum correlations versus spin magnitude: Transition to the classical limit
• Authors: M. A. Yurischev, E. I. Kuznetsova, Saeed Haddadi,
• Abstract summary: We study transitions in quantum spin-($j$,1/2) systems at thermal equilibrium.<n>The discord-type quantum correlations can exist even for arbitrarily large spin.<n>The stable quantum correlations gradually degrade as the spin $j$ grows and eventually vanish when the classical limit is reached.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Quantum-classical transitions have long attracted much attention. We study such transitions in quantum spin-($j$,1/2) systems at thermal equilibrium. Unlike previous papers, it is found that the threshold temperature of quantum entanglement decreases with increasing spin $j$ and completely disappears in the limit $j\to\infty$. In the ground state of systems with highly symmetric interactions, the discord-type quantum correlations can exist even for arbitrarily large spin. Such correlations turn out to be unstable and are destroyed by small perturbations that violate the symmetry of the Hamiltonian. The stable quantum correlations gradually degrade as the spin $j$ grows and eventually vanish when the classical limit is reached.

Related papers

• Quantum simulation of bubble nucleation across a quantum phase transition [31.874825130479174]
  We use a trapped-ion quantum simulator to observe the real-time dynamics of bubble nucleation'' induced by quantum fluctuations.<n>Results demonstrate the power of quantum simulators to probe out-of-equilibrium many-body physics.
  arXiv  Detail & Related papers  (2025-05-14T17:57:25Z)
• Discord-type quantum correlations in axially symmetric spin-(1/2, $S$) systems [0.0]
  We study a mixed spin-$(1/2, S)$ system with arbitrary spin $S$ and interactions satisfying the U(1) axial symmetry. We find that as the system cools, quantum correlations can undergo one or more abrupt transitions while the temperature changes smoothly.
  arXiv  Detail & Related papers  (2024-04-11T21:04:25Z)
• Waveguide quantum electrodynamics at the onset of spin-spin correlations [36.136619420474766]
  We find that molecules belonging to one of the two crystal sublattices form one-dimensional spin chains.<n>The microwave transmission shows evidences for the collective coupling of quasi-identical spins to the propagating photons.
  arXiv  Detail & Related papers  (2024-04-04T18:00:05Z)
• Quantumness and quantum to classical transition in the generalized Rabi model [17.03191662568079]
  We define the quantumness of a Hamiltonian by the free energy difference between its quantum and classical descriptions. We show that the Jaynes-Cummings and anti Jaynes-Cummings models exhibit greater quantumness than the Rabi model.
  arXiv  Detail & Related papers  (2023-11-12T18:24:36Z)
• Reconstructing the spatial structure of quantum correlations in materials [0.0]
  Quantum correlations are a fundamental property of many-body states. Yet they remain elusive, hindering certification of genuine quantum materials. We show that momentumdependent dynamical behavior via neutron scattering enables a general family of quantum correlation.
  arXiv  Detail & Related papers  (2023-06-20T17:55:09Z)
• Observing super-quantum correlations across the exceptional point in a single, two-level trapped ion [48.7576911714538]
  In two-level quantum systems - qubits - unitary dynamics theoretically limit these quantum correlations to $2qrt2$ or 1.5 respectively. Here, using a dissipative, trapped $40$Ca$+$ ion governed by a two-level, non-Hermitian Hamiltonian, we observe correlation values up to 1.703(4) for the Leggett-Garg parameter $K_3$. These excesses occur across the exceptional point of the parity-time symmetric Hamiltonian responsible for the qubit's non-unitary, coherent dynamics.
  arXiv  Detail & Related papers  (2023-04-24T19:44:41Z)
• Scalable Spin Squeezing from Finite Temperature Easy-plane Magnetism [26.584014467399378]
  We conjecture that any Hamiltonian exhibiting finite temperature, easy-plane ferromagnetism can be used to generate scalable spin squeezing. Our results provide insights into the landscape of Hamiltonians that can be used to generate metrologically useful quantum states.
  arXiv  Detail & Related papers  (2023-01-23T18:59:59Z)
• Quantum and classical correlations in open quantum-spin lattices via truncated-cumulant trajectories [0.0]
  We show a new method to treat open quantum-spin lattices, based on the solution of the open-system dynamics. We validate this approach in the paradigmatic case of the phase transitions of the dissipative 2D XYZ lattice, subject to spontaneous decay.
  arXiv  Detail & Related papers  (2022-09-27T13:23:38Z)
• Scalable spin squeezing from spontaneous breaking of a continuous symmetry [0.0]
  In systems of $S=1/2$ or qubits, the combination of the suppression of fluctuations along one direction and of the persistence of transverse magnetization leads to spin squeezing. Our findings open the door to the adiabatic preparation of strongly spin-squeezed states in a large variety of quantum many-body devices including e.g. optical lattice clocks.
  arXiv  Detail & Related papers  (2022-02-17T11:41:30Z)
• Out-of-time-order correlator in the quantum Rabi model [62.997667081978825]
  We show that out-of-time-order correlator derived from the Loschmidt echo signal quickly saturates in the normal phase. We show that the effective time-averaged dimension of the quantum Rabi system can be large compared to the spin system size.
  arXiv  Detail & Related papers  (2022-01-17T10:56:57Z)
• Quantum versus thermal fluctuations in the harmonic chain and experimental implications [0.0]
  The transition from pure quantum fluctuations at $T=0$ to classical thermal fluctuations in the high temperature limit is described. The absence of sharp Bragg peaks in x-ray scattering in an infinite chain at zero temperature shows power law behaviour typical for one dimensional quantum liquids.
  arXiv  Detail & Related papers  (2020-08-25T13:44:39Z)
• Quantum Statistical Complexity Measure as a Signalling of Correlation Transitions [55.41644538483948]
  We introduce a quantum version for the statistical complexity measure, in the context of quantum information theory, and use it as a signalling function of quantum order-disorder transitions. We apply our measure to two exactly solvable Hamiltonian models, namely: the $1D$-Quantum Ising Model and the Heisenberg XXZ spin-$1/2$ chain. We also compute this measure for one-qubit and two-qubit reduced states for the considered models, and analyse its behaviour across its quantum phase transitions for finite system sizes as well as in the thermodynamic limit by using Bethe ansatz.
  arXiv  Detail & Related papers  (2020-02-05T00:45:21Z)

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.