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We consider the effective dynamics obtained by double-passing a far-detuned laser probe through a large atomic spin system. The net result of the atom-field interaction is a type of coherent positive feedback that amplifies the values of…

Quantum Physics · Physics 2009-05-08 Bradley A. Chase , JM Geremia

Thermally assisted magnetic writing is an important technology utilizing temperature dependent magnetic properties to enable orientation of a magnetic data storage medium. Using an atomistic spin model we study non-equilibrium field cooled…

Mesoscale and Nanoscale Physics · Physics 2014-09-26 R. F. L. Evans , W. J. Fan

Including quantum mechanical effects on the dynamics of nuclei in the condensed phase is challenging, because the complexity of exact methods grows exponentially with the number of quantum degrees of freedom. Efforts to circumvent these…

Chemical Physics · Physics 2015-06-23 Mariana Rossi , Hanchao Liu , Francesco Paesani , Joel Bowman , Michele Ceriotti

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…

Quantum Physics · Physics 2025-06-18 Thomas Nussle , Stam Nicolis , Iason Sofos , Joseph Barker

We present a comprehensive comparison of spin and energy dynamics in quantum and classical spin models on different geometries, ranging from one-dimensional chains, over quasi-one-dimensional ladders, to two-dimensional square lattices.…

Statistical Mechanics · Physics 2021-08-27 Dennis Schubert , Jonas Richter , Fengping Jin , Kristel Michielsen , Hans De Raedt , Robin Steinigeweg

Many interesting problems in physics, chemistry, and computer science are equivalent to problems of interacting spins. However, most of these problems require computational resources that are out of reach by classical computers. A promising…

Quantum Physics · Physics 2012-06-07 Jingfu Zhang , Man-Hong Yung , Raymond Laflamme , Alán Aspuru-Guzik , Jonathan Baugh

Low-temperature magnetic properties of both classical and quantum dimerized ferromagnetic spin chains are studied. It is shown that at low temperatures the classical dimerized model reduces to the classical uniform model with the effective…

Strongly Correlated Electrons · Physics 2013-05-30 D. V. Dmitriev , V. Ya. Krivnov

Classical simulations of high-temperature nuclear spin dynamics in solids are known to accurately predict relaxation for spin 1/2 lattices with a large number of interacting neighbors. Once the number of interacting neighbors becomes four…

Strongly Correlated Electrons · Physics 2019-02-20 Patrick Navez , Grigory A. Starkov , Boris V. Fine

Quantum simulation aims to recreate complex many-body phenomena in controlled environments, offering insights into dynamics that are otherwise difficult to model. Existing platforms, however, are often complex and costly to scale, typically…

A simple and computationally efficient algorithm enables implementing negative temperature values in a spin dynamics simulation. The algorithm uses a Langevin spin dynamics thermostat with a negative damping parameter, enabling the…

Materials Science · Physics 2024-03-05 Pui-Wai Ma , Sergei L. Dudarev

Classical nonlinear theories are highly successful in describing far-from-equilibrium dynamics of magnets, encompassing phenomena such as parametric resonance, ultrafast switching, and even chaos. However, at ultrashort length and time…

Mesoscale and Nanoscale Physics · Physics 2025-12-15 Lukas Körber , Pim Coenders , Johan H. Mentink

Classical and path integral molecular dynamics (PIMD) simulations are used to study alpha-quartz and beta-quartz in a large range of temperatures at zero external stress. PIMD account for quantum fluctuations of atomic vibrations, which can…

Materials Science · Physics 2015-06-24 Martin H. Muser

We investigate the limits of effectiveness of classical spin simulations for predicting free induction decays (FIDs) measured by solid-state nuclear magnetic resonance (NMR) on systems of quantum nuclear spins. The specific limits…

Quantum Physics · Physics 2015-06-23 Tarek A. Elsayed , Boris V. Fine

We consider spin dynamics for implementation in an atomistic framework and we address the feasibility of capturing processes in the femtosecond regime by inclusion of moment of inertia. In the spirit of an {\it s-d} -like interaction…

Statistical Mechanics · Physics 2012-02-02 S. Bhattacharjee , L. Nordström , J. Fransson

Laser-cooled and trapped atomic ions form an ideal standard for the simulation of interacting quantum spin models. Effective spins are represented by appropriate internal energy levels within each ion, and the spins can be measured with…

The phenomenological Landau theory of the spin precession has been used to reproduce the out-of-equilibrium properties of many magnetic systems. However, such an approach suffers from some serious limitations. The main reason is that the…

Mesoscale and Nanoscale Physics · Physics 2016-06-20 O. Morandi

We study interaction effects on the orbital magnetism of diffusive mesoscopic quantum systems. By combining many-body perturbation theory with semiclassical techniques, we show that the interaction contribution to the ensemble averaged…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 D. Ullmo , K. Richter , H. U. Baranger , F. von Oppen , R. A. Jalabert

We simulate the dynamical spin structure factor (DSSF) $\mathcal{S}({q},\omega)$ of the spin-1/2 Heisenberg antiferromagnetic chain using classical simulations. By employing Landau-Lifshitz Dynamics, we emulate quantum correlations through…

Strongly Correlated Electrons · Physics 2026-01-15 Chaebin Kim , Martin Mourigal

Previous experimental realizations of Dicke model in atomic or ionic systems are based on global observables assuming uniform spin-boson coupling, while inevitable experimental nonuniformity on the one hand requires site-resolved…

In this article, a few problems related to multiscale modelling of magnetic materials at finite temperatures and possible ways of solving these problems are discussed. The discussion is mainly centred around two established multiscale…

Computational Physics · Physics 2017-02-20 Doghonay Arjmand , Mikhail Poluektov , Gunilla Kreiss