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We consider the random transverse-field Ising model in $d=3$ dimensions with long-range ferromagnetic interactions which decay as a power $\alpha > d$ with the distance. Using a variant of the strong disorder renormalization group method we…

Statistical Mechanics · Physics 2016-06-08 István A. Kovács , Róbert Juhász , Ferenc Iglói

We investigate the phase structure of the random-field Ising model with a bimodal random field distribution. Our aim is to test for the possibility of an equilibrium spin-glass phase, and for replica symmetry breaking (RSB) within such a…

Disordered Systems and Neural Networks · Physics 2009-11-07 Jairo Sinova , Geoff Canright

The random field Ising model is studied numerically at both zero and positive temperature. Ground states are mapped out in a region of random and external field strength. Thermal states and thermodynamic properties are obtained for all…

Statistical Mechanics · Physics 2009-11-11 Yong Wu , Jon Machta

The four dimensional Gaussian random field Ising magnet is investigated numerically at zero temperature, using samples up to size $64^4$, to test scaling theories and to investigate the nature of domain walls and the thermodynamic limit. As…

Disordered Systems and Neural Networks · Physics 2007-05-23 A. Alan Middleton

We study the correlated-disorder driven zero-temperature phase transition of the Random-Field Ising Magnet using exact numerical ground-state calculations for cubic lattices. We consider correlations of the quenched disorder decaying…

Disordered Systems and Neural Networks · Physics 2015-05-28 Björn Ahrens , Alexander K. Hartmann

The sensitivity of the random field Ising model to small random perturbations of the quenched disorder is studied via exact ground states obtained with a maximum-flow algorithm. In one and two space dimensions we find a mild form of chaos,…

Disordered Systems and Neural Networks · Physics 2009-10-31 M. Alava , H. Rieger

We study hysteresis for a two-dimensional, spin-1/2, nearest-neighbor, kinetic Ising ferromagnet in an oscillating field, using Monte Carlo simulations and analytical theory. Attention is focused on small systems and weak field amplitudes…

Materials Science · Physics 2009-10-30 S. W. Sides , P. A. Rikvold , M. A. Novotny

Dynamics of Ising models is a much studied phenomenon and has emerged as a rich field of present-day research. An important dynamical feature commonly studied is the quenching phenomenon below the critical temperature. In this thesis we…

Statistical Mechanics · Physics 2016-03-08 Soham Biswas

Using a Wang-Landau entropic sampling scheme, we investigate the effects of quenched bond randomness on a particular case of a triangular Ising model with nearest- ($J_{nn}$) and next-nearest-neighbor ($J_{nnn}$) antiferromagnetic…

Statistical Mechanics · Physics 2009-10-28 N. G. Fytas , A. Malakis

We investigate the temperature dependence of the finite-field magnetization of the S=1/2 bond-alternating XY model in the Random magnetic field along the z-direction having the Lorentzian distribution. The random-averaged free energy can be…

Strongly Correlated Electrons · Physics 2015-10-28 Kiyomi Okamoto

We investigate, by means of extensive Monte Carlo simulations, the magnetic critical behavior of the three-dimensional bimodal random-field Ising model at the strong disorder regime. We present results in favor of the two-exponent scaling…

Statistical Mechanics · Physics 2011-02-09 N. G. Fytas , A. Malakis

The main goal of the paper is to prove central limit theorems for the magnetization rescaled by $\sqrt{N}$ for the Ising model on random graphs with $N$ vertices. Both random quenched and averaged quenched measures are considered. We work…

The Ginzburg-Landau model below its critical temperature in a temporally oscillating external field is studied both theoretically and numerically. As the frequency or the amplitude of the external force is changed, a nonequilibrium phase…

Statistical Mechanics · Physics 2009-10-31 H. Fujisaka , H. Tutu , P. A. Rikvold

The spin structure of an axial next-nearest-neighbor Ising (ANNNI) model in two dimensions (2D) is a renewed problem because different Monte Carlo (MC) simulation methods predicted different spin orderings. The usual equilibrium simulation…

Disordered Systems and Neural Networks · Physics 2015-06-22 T. Shirakura , F. Matsubara , N. Suzuki

Ground states of three-dimensional EA Ising spin glasses are calculated for sizes up to 14^3 using a combination of a genetic algorithm and cluster-exact approximation. For each realization several independent ground states are obtained.…

Disordered Systems and Neural Networks · Physics 2015-06-25 Alexander K. Hartmann

We study the three-dimensional Ising model at the critical point in the fixed-magnetization ensemble, by means of the recently developed geometric cluster Monte Carlo algorithm. We define a magnetic-field-like quantity in terms of…

Statistical Mechanics · Physics 2009-10-31 H. W. J. Blöte , J. R. Heringa , M. M. Tsypin

During the past decades, the Ising distribution has attracted interest in many applied disciplines, as the maximum entropy distribution associated to any set of correlated binary (`spin') variables with observed means and covariances.…

Disordered Systems and Neural Networks · Physics 2019-05-13 Adrien Wohrer

We employ the microcanonical inflection-point analysis method, developed for the systematic identification and classification of phase transitions in systems of any size, to study the two-dimensional Ising model at various lattice sizes and…

Statistical Mechanics · Physics 2023-06-30 Kedkanok Sitarachu , Michael Bachmann

We reconsider Ising spins in a Gaussian random field within the replica formalism. The corresponding continuum model involves several coupling constants beyond the single one which was considered in the standard $\phi^4$ theory approach.…

Condensed Matter · Physics 2009-10-31 E. Brézin , C. De Dominicis

Using the self-consistent Ornstein-Zernike approximation (SCOZA) results for the 3D Ising model, we obtain phase diagrams for binary mixtures described by decorated models. We obtain the plait point, binodals, and closed-loop coexistence…

Statistical Mechanics · Physics 2009-11-07 Adriana G. Dickman , G. Stell