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A dynamics of the precession of coupled atomic moments in the tight-binding (TB) approximation is presented. By implementing an angular penalty functional in the energy that captures the magnetic effective fields self-consistently, the…

Materials Science · Physics 2021-07-07 Ramon Cardias , Cyrille Barreteau , Pascal Thibaudeau , Chu Chun Fu

We investigate a specific limit of the one-dimensional non-Hermitian Hubbard Hamiltonian with complex interactions. In this framework, fermions with different spin quantum numbers are mapped onto two distinct spin species, resulting in two…

Statistical Mechanics · Physics 2024-12-30 Doru Sticlet , Cătălin Paşcu Moca , Balázs Dóra

We study the low temperature dynamics of a two dimensional short-range spin system with uniform ferromagnetic interactions, which displays glassiness at low temperatures despite the absence of disorder or frustration. The model has a dual…

Disordered Systems and Neural Networks · Physics 2009-10-31 Juan P. Garrahan , M. E. J. Newman

Laser induced modulation of the magnetization dynamics occurring over various time-scales have been unified here for a Ni80Fe20 thin film excited by amplified femtosecond laser pulses. The weak correlation between demagnetization time and…

Mesoscale and Nanoscale Physics · Physics 2018-12-21 Sucheta Mondal , Anjan Barman

A dynamic mean-field theory for spin ensembles (spinDMFT) at infinite temperatures on arbitrary lattices is established. The approach is introduced for an isotropic Heisenberg model with $S = \tfrac12$ and external field. For large…

Statistical Mechanics · Physics 2022-02-03 Timo Gräßer , Philip Bleicker , Dag-Björn Hering , Mohsen Yarmohammadi , Götz S. Uhrig

We report on {\it ab initio} time-dependent spin dynamics simulations for a two-center magnetic molecular complex based on time-dependent non-collinear spin density functional theory. In particular, we discuss how the dynamical behavior of…

Other Condensed Matter · Physics 2015-06-16 Maria Stamenova , Stefano Sanvito

Atomistic simulations of thermodynamic properties of magnetic materials rely on an accurate modelling of magnetic interactions and an efficient sampling of the high-dimensional spin space. Recent years have seen significant progress with a…

Statistical Mechanics · Physics 2019-03-27 Ning Wang , Thomas Hammerschmidt , Jutta Rogal , Ralf Drautz

Precise modeling of the magnetization dynamics of nanoparticles with finite size effects at fast varying temperatures is a computationally challenging task. Based on the Landau-Lifshitz-Bloch (LLB) equation we derive a coarse grained model…

Materials Science · Physics 2019-08-07 Christoph Vogler , Claas Abert , Florian Bruckner , Dieter Suess

A microscopic view of the response of the electric dipoles to a dynamic external field in a ferroelectric (FE) chain has been studied by two spin dynamics methods. One is the prominent micromagnetic approach, and the other is the…

Mesoscale and Nanoscale Physics · Physics 2015-12-08 Zidong Wang , Malcolm J. Grimson

We study the low-temperature physics of the $SU(2)$-symmetric spin-$1/2$ Heisenberg antiferromagnet on a pyrochlore lattice and find fingerprint evidence for the thermal spin-ice state in this frustrated quantum magnet. Our conclusions are…

Strongly Correlated Electrons · Physics 2016-05-04 Yuan Huang , Kun Chen , Youjin Deng , Nikolay Prokof'ev , Boris Svistunov

We present a method for performing atomistic spin dynamic simulations. A comprehensive summary of all pertinent details for performing the simulations such as equations of motions, models for including temperature, methods of extracting…

Materials Science · Physics 2014-04-04 B. Skubic , J. Hellsvik , L. Nordström , O. Eriksson

We study the far-from-equilibrium properties of quenched magnetic nanoscopic classical spin systems. In particular, we focus on the interplay between lattice vibrations and magnetic frustrations induced by surface effects typical of an…

Mesoscale and Nanoscale Physics · Physics 2020-01-01 Carla Lupo , Cedric Weber

Spin-dynamics simulations have been used to investigate the dynamic behavior of RbMnF_3, treating it as a classical Heisenberg antiferromagnet on a simple cubic lattice. Time-evolutions of spin configurations were determined numerically…

Statistical Mechanics · Physics 2016-08-31 D. P. Landau , Shan-Ho Tsai , Alex Bunker

We employ a thermodynamic integration method (TIM) to establish the values of the residual entropy for the geometrically frustrated spin-s triangular Ising antiferromagnet, with the spin values s = 1/2, 1, 3/2, 2 and 5/2. The case of s =…

Statistical Mechanics · Physics 2013-06-25 M. Žukovič

We study theoretically the far-from-equilibrium relaxation dynamics of spin spiral states in the three dimensional isotropic Heisenberg model. The investigated problem serves as an archetype for understanding quantum dynamics of isolated…

Quantum Gases · Physics 2015-10-14 Mehrtash Babadi , Eugene Demler , Michael Knap

A method is proposed for obtaining a systematic expansion of thermodynamic functions of spin systems with large spin S in powers of 1/S. It uses the cumulant technique and a coherent-state representation of the partition function Z. The…

Statistical Mechanics · Physics 2009-10-31 K. Kladko , P. Fulde , D. A. Garanin

We use our recently developed functional renormalization group (FRG) approach for quantum spin systems to investigate the phase diagram of the frustrated $J_{1}J_{2}J_{3}$ quantum Heisenberg model on a cubic lattice. From a simple…

Strongly Correlated Electrons · Physics 2023-02-28 Dmytro Tarasevych , Andreas Rückriegel , Savio Keupert , Vasilios Mitsiioannou , Peter Kopietz

We have performed a large scale Monte Carlo simulation of a dilute classical Heisenberg model with ferromagnetic nearest neighbor and antiferromagnetic next-nearest neighbor interactions. We found that the model reproduces a reentrant…

Disordered Systems and Neural Networks · Physics 2009-11-11 S. Abiko , S. Niidera , F. Matsubara

By developing a semi-classical analysis based on the Eigenstate Thermalization Hypothesis, we determine the long time behavior of a large spin evolving with a nonlinear Hamiltonian. Despite integrable classical dynamics, we find the…

Quantum Physics · Physics 2020-11-10 Shane P. Kelly , Eddy Timmermans , S. -W. Tsai

Itinerant ferromagnetism in cold Fermi gases with repulsive interactions is studied applying the Jastrow-Slater approximation generalized to finite polarization and temperature. For two components at zero temperature a second order…

Quantum Gases · Physics 2015-05-20 Henning Heiselberg