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In order to single out dominant phenomena that account for carrier-controlled magnetism in p-(Cd,Mn)Te quantum wells we have carried out magneto-optical measurements and Monte Carlo simulations of time dependent magnetization. The…

Materials Science · Physics 2014-01-03 A. Lipinska , C. Simserides , K. N. Trohidou , M. Goryca , P. Kossacki , A. Majhofer , T. Dietl

A one-dimensional model of electrons locally coupled to spin-1/2 degrees of freedom is studied by numerical techniques. The model is one in the class of $dynamic$ $Hubbard$ $models$ that describe the relaxation of an atomic orbital upon…

Strongly Correlated Electrons · Physics 2009-11-07 J. E. Hirsch

We present Tethered Monte Carlo, a simple, general purpose method of computing the effective potential of the order parameter (Helmholtz free energy). This formalism is based on a new statistical ensemble, closely related to the…

Statistical Mechanics · Physics 2009-08-11 L. A. Fernandez , V. Martin-Mayor , D. Yllanes

We introduce a general Monte Carlo scheme for achieving atomistic simulations with monoelectronic Hamiltonians including the thermalization of both nuclear and electronic degrees of freedom. The kinetic Monte Carlo algorithm is used to…

Materials Science · Physics 2009-11-07 F. Calvo , F. Spiegelman

Monte Carlo simulations are performed in classical phase space for a one-dimensional quantum harmonic crystal. Symmetrization effects for spinless bosons and fermions are quantified. The algorithm is tested for a range of parameters against…

Quantum Physics · Physics 2019-04-25 Phil Attard

Computation of ionic forces using quantum Monte Carlo methods has long been a challenge. We introduce a simple procedure, based on known properties of physical electronic densities, to make the variance of the Hellmann-Feynman estimator…

Computational Physics · Physics 2007-05-23 Simone Chiesa , David Ceperley , Shiwei Zhang

The low-energy constants, namely the spin stiffness $\rho_s$, the staggered magnetization density ${\cal M}_s$ per area, and the spinwave velocity $c$ of the two-dimensional (2D) spin-1 Heisenberg model on the square and rectangular…

Strongly Correlated Electrons · Physics 2018-01-17 Fu-Jiun Jiang

We present a massively parallel quantum Monte Carlo based implementation of real-space dynamical mean-field theory for general inhomogeneous correlated fermionic lattice systems. As a first application, we study magnetic order in a binary…

Quantum Gases · Physics 2010-12-16 N. Blümer , E. V. Gorelik

We describe results of Monte Carlo simulations on a model that seems to have the necessary ingredients to describe a disordered type-II superconductor in a magnetic field. We compute the free energy cost to twist the direction of the phase…

Condensed Matter · Physics 2007-05-23 J. D. Reger , A. P. Young

We simulate the spin-1/2 Heisenberg model with a spatially staggered anisotropy using first principles Monte Carlo method. In particular, the critical exponents $\beta/\nu$ and $\omega$ associated with the quantum phase transition induced…

Strongly Correlated Electrons · Physics 2013-07-24 F. -J. Jiang

Motivated by recent experiments with a Penning ion trap quantum simulator, we perform numerically exact Stochastic Series Expansion quantum Monte Carlo simulations of long-range transverse-field Ising models on a triangular lattice for…

Statistical Mechanics · Physics 2016-03-15 Stephan Humeniuk

Direct sampling of multi-dimensional systems with quantum Monte Carlo methods allows exact account of many-body effects or particle correlations. The most straightforward approach to solve the Schr\"odinger equation, Diffusion Monte Carlo,…

Quantum Physics · Physics 2017-09-07 Ilkka Ruokosenmäki , Tapio T. Rantala

The canonical one-band Hubbard model is studied using a computational method that mixes the Monte Carlo procedure with the mean field approximation. This technique allows us to incorporate thermal fluctuations and the development of…

Strongly Correlated Electrons · Physics 2014-11-25 Anamitra Mukherjee , Niravkumar D. Patel , Shuai Dong , Steve Johnston , Adriana Moreo , Elbio Dagotto

Monte Carlo simulations of lattice quantum field theories on Lefschetz thimbles are non trivial. We discuss a new Monte Carlo algorithm based on the idea of computing contributions to the functional integral which come from complete flow…

High Energy Physics - Lattice · Physics 2016-11-28 Francesco Di Renzo , Giovanni Eruzzi

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

The antiferromagnetic Heisenberg model is studied on a two-dimensional bipartite quasiperiodic lattice. The distribution of local staggered magnetic moments is determined on finite square approximants with up to 1393 sites, using the…

Strongly Correlated Electrons · Physics 2016-08-31 Stefan Wessel , Anuradha Jagannathan , Stephan Haas

We analyze the temperature dependence of the entropy of the spin-1/2 Heisenberg model on the three-dimensional simple-cubic lattice, for both the case of antiferromagnetic and ferromagnetic nearest neighbor exchange interactions. Using…

Strongly Correlated Electrons · Physics 2015-05-14 Stefan Wessel

In this paper, we study the effect of both an external and crystal magnetic fields for a superlattice with mixed spins (1/2, 1), using Monte Carlo simulations. The ground state phase diagrams, in the external magnetic field, coupling…

Strongly Correlated Electrons · Physics 2017-11-07 A. Mhirech , L. Bahmad

We consider quantum Heisenberg ferro- and antiferromagnets on the square lattice with exchange anisotropy of easy-plane or easy-axis type. The thermodynamics and the critical behaviour of the models are studied by the pure-quantum…

Statistical Mechanics · Physics 2015-06-24 A. Cuccoli , T. Roscilde , V. Tognetti , R. Vaia , P. Verrucchi

We study thermodynamic properties as well as the dynamical spin and quadrupolar structure factors of the O(3)-symmetric spin-1 Heisenberg model with bilinear-biquadratic exchange interactions on the triangular lattice. Based on a…

Strongly Correlated Electrons · Physics 2016-03-01 Annika Völl , Stefan Wessel