Path integral spin dynamics with exchange and external field

• URL: http://arxiv.org/abs/2502.19113v2
• Date: Tue, 17 Jun 2025 10:49:50 GMT
• Title: Path integral spin dynamics with exchange and external field
• Authors: Thomas Nussle, Stam Nicolis, Iason Sofos, Joseph Barker,
• Abstract summary: We propose a path integral-inspired formalism for computing the quantum thermal expectation values of spin systems.<n>This is done by deriving an effective magnetic field from the quantum partition function of the system.<n>We show that our method works well across a large temperature range and can reproduce quantum expectation values for antiferromagnetic coupling.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In this work, we propose a path integral-inspired formalism for computing the quantum thermal expectation values of spin systems, when subject to magnetic fields that can be time-dependent and can accommodate the presence of Heisenberg exchange interactions between the spins. This is done by deriving an effective magnetic field from the quantum partition function of the system to use in classical atomistic spin dynamics simulations and generalises the formalism presented in our previous work [Phys. Rev. Research 5, 043075 (2023)]. In special cases where the effective field can be computed exactly we compare our results with exact/numerical diagonalisation methods for both ferromagnetic and antiferromagnetic coupling. We show that our method works well across a large temperature range and can reproduce quantum expectation values for antiferromagnetic coupling which is usually not possible with classical models.

Related papers

• Observation of Magnetic Devil's Staircase-Like Behavior in Quasiperiodic Qubit Lattices [55.2480439325792]
  devil's staircase (DS) phenomenon is a fractal response of magnetization to external fields.<n>We uncover a wealth of abrupt magnetic transitions driven by increasing external magnetic fields within a simple yet effective Ising-model framework.<n>Our results challenge the prevailing view that DS behavior is limited to periodic systems.
  arXiv  Detail & Related papers  (2025-07-24T21:39:06Z)
• Quantum computing of magnetic-skyrmion-like patterns in Heisenberg ferromagnets [0.0]
  We diagonalize the quantum two-dimensional spin-1/2 Heisenberg model with Dzyaloshinskii-Moriya interaction (DMI)<n>The calculated external-magnetic-field dependence of the total energy, of the magnetization, as well as of the topological charge exhibits a distinctive discontinuity.<n>The investigated objects are stable enough for eventual applications in spintronics or even as information carriers.
  arXiv  Detail & Related papers  (2025-05-26T10:45:43Z)
• Emergent Kitaev materials in synthetic Fermi-Hubbard bilayers [49.1574468325115]
  Bond-directional spin-spin interactions in a Fermi-Hubbard bilayer can be realized with ultracold fermions in Raman optical lattices.<n>We analyze the Fermi-liquid and Mott-insulating phases, highlighting a correspondence between Dirac and Majorana quasi-particles.<n>Our results establish that cold-atom quantum simulators based on Raman optical lattices can be a playground for extended Kitaev models.
  arXiv  Detail & Related papers  (2025-04-22T10:07:56Z)
• A relativistic QFT description for the interaction of a spin with a magnetic field [0.0]
  We analyze how non-relativistic effective models for the magnetic coupling of a spin to the electromagnetic field emerge.<n>This allows us to keep track of relativistic corrections to the models commonly used in experimental spin physics.
  arXiv  Detail & Related papers  (2024-11-21T19:00:00Z)
• Path integral spin dynamics for quantum paramagnets [0.0]
  We show how to treat Hamiltonians with non-linear terms, that are relevant for describing uniaxial anisotropies and mechanical constraints. These interactions can be expressed solely through quadratic terms of the spin operator along one axis, that can be identified with the quantisation axis.
  arXiv  Detail & Related papers  (2024-04-30T13:13:58Z)
• Anisotropy-induced spin parity effects [0.0]
  A dichotomy in the physical behavior of a system arises, solely depending on whether the relevant spin quantum number is integral or half-odd integral. Here, we put forth a simple and general scheme for generating such effects in any spatial dimension through the use of anisotropic interactions. We demonstrate its utility through a detailed analysis of the magnetization behavior of a specific one-dimensional spin chain model, an anisotropic antiferromagnet in a transverse magnetic field.
  arXiv  Detail & Related papers  (2024-02-29T16:15:43Z)
• A Floquet-Rydberg quantum simulator for confinement in $\mathbb{Z}_2$ gauge theories [44.99833362998488]
  Recent advances in the field of quantum technologies have opened up the road for the realization of small-scale quantum simulators. We present a scalable Floquet scheme for the quantum simulation of the real-time dynamics in a $mathbbZ$ LGT. We show that an observation of gauge-invariant confinement dynamics in the Floquet-Rydberg setup is at reach of current experimental techniques.
  arXiv  Detail & Related papers  (2023-11-28T13:01:24Z)
• The Weakly Bound States in Gaussian Wells: From the Binding Energy of Deuteron to the Electronic Structure of Quantum Dots [0.0]
  This study focuses on examining the lowest states within Gaussian wells, with particular emphasis on the weakly bound regime. The analysis delves into the behavior of the exact wave function at both small and large distances, motivating the development of a few-parametric Ansatz. In concluding our investigation, we evaluate the performance of our Ansatz as an orbital in the exploration of the electronic structure of a two-electron quantum dot.
  arXiv  Detail & Related papers  (2023-11-05T20:48:12Z)
• A high-flux source system for matter-wave interferometry exploiting tunable interactions [33.92525320044496]
  Atom interferometers allow determining inertial effects to high accuracy. Here we report on a high-flux source of ultra-cold atoms with free expansion rates near the Heisenberg limit directly upon release from the trap.
  arXiv  Detail & Related papers  (2023-07-13T14:10:53Z)
• First-order transitions in spin chains coupled to quantum baths [0.0]
  We show that tailoring the dissipative environment allows to change the features of continuous quantum phase transitions. We find that spin couplings to local quantum boson baths in the Ohmic regime can drive the transition from the second to the first order even for a low dissipation strength.
  arXiv  Detail & Related papers  (2022-07-27T20:42:08Z)
• Tuning long-range fermion-mediated interactions in cold-atom quantum simulators [68.8204255655161]
  Engineering long-range interactions in cold-atom quantum simulators can lead to exotic quantum many-body behavior. Here, we propose several tuning knobs, accessible in current experimental platforms, that allow to further control the range and shape of the mediated interactions.
  arXiv  Detail & Related papers  (2022-03-31T13:32:12Z)
• Accessing the topological Mott insulator in cold atom quantum simulators with realistic Rydberg dressing [58.720142291102135]
  We investigate a realistic scenario for the quantum simulation of such systems using cold Rydberg-dressed atoms in optical lattices. We perform a detailed analysis of the phase diagram at half- and incommensurate fillings, in the mean-field approximation. We furthermore study the stability of the phases with respect to temperature within the mean-field approximation.
  arXiv  Detail & Related papers  (2022-03-28T14:55:28Z)
• Time evolution of spin singlet in static homogeneous exchange and magnetic fields [0.0]
  We study the effect of external static homogeneous exchange and magnetic field on the spin part of the singlet wave function of two electrons. Some applications of our results to the theory of superconductivity and spin chemistry are presented.
  arXiv  Detail & Related papers  (2021-11-08T14:54:59Z)
• 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)
• Machine Learning S-Wave Scattering Phase Shifts Bypassing the Radial Schr\"odinger Equation [77.34726150561087]
  We present a proof of concept machine learning model resting on a convolutional neural network capable to yield accurate scattering s-wave phase shifts. We discuss how the Hamiltonian can serve as a guiding principle in the construction of a physically-motivated descriptor.
  arXiv  Detail & Related papers  (2021-06-25T17:25:38Z)
• Realistic simulations of spin squeezing and cooperative coupling effects in large ensembles of interacting two-level systems [0.0]
  We describe an efficient numerical method for simulating the dynamics of interacting spin ensembles in the presence of dephasing and decay. This opens up the possibility to perform accurate real-scale simulations of a diverse range of experiments in quantum optics or with solid-state spin ensembles under realistic laboratory conditions.
  arXiv  Detail & Related papers  (2021-04-30T18:00:00Z)
• Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla [50.002949299918136]
  We show that [VO(TPP)] (vanadyl tetraphenylporphyrinate) is a promising system suitable to implement quantum computation algorithms. It embeds an electronic spin 1/2 coupled through hyperfine interaction to a nuclear spin 7/2, both characterized by remarkable coherence.
  arXiv  Detail & Related papers  (2021-03-15T21:38:41Z)
• Bernstein-Greene-Kruskal approach for the quantum Vlasov equation [91.3755431537592]
  The one-dimensional stationary quantum Vlasov equation is analyzed using the energy as one of the dynamical variables. In the semiclassical case where quantum tunneling effects are small, an infinite series solution is developed.
  arXiv  Detail & Related papers  (2021-02-18T20:55:04Z)
• Spin Entanglement and Magnetic Competition via Long-range Interactions in Spinor Quantum Optical Lattices [62.997667081978825]
  We study the effects of cavity mediated long range magnetic interactions and optical lattices in ultracold matter. We find that global interactions modify the underlying magnetic character of the system while introducing competition scenarios. These allow new alternatives toward the design of robust mechanisms for quantum information purposes.
  arXiv  Detail & Related papers  (2020-11-16T08:03:44Z)
• State preparation and measurement in a quantum simulation of the O(3) sigma model [65.01359242860215]
  We show that fixed points of the non-linear O(3) sigma model can be reproduced near a quantum phase transition of a spin model with just two qubits per lattice site. We apply Trotter methods to obtain results for the complexity of adiabatic ground state preparation in both the weak-coupling and quantum-critical regimes. We present and analyze a quantum algorithm based on non-unitary randomized simulation methods.
  arXiv  Detail & Related papers  (2020-06-28T23:44:12Z)
• Adiabatic preparation of entangled, magnetically ordered states with cold bosons in optical lattices [0.0]
  We analyze a scheme for preparation of magnetically ordered states of bosonic atoms in optical lattices. We compute the dynamics during adiabatic and optimized time-dependent ramps to produce ground states of effective spin Hamiltonians.
  arXiv  Detail & Related papers  (2020-03-23T17:43:41Z)

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.