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We investigate the phase transition in a strongly disordered short-range three-spin interaction model characterized by the absence of time reversal symmetry in the Hamiltonian. In the mean-field limit the model is well described by the…

Condensed Matter · Physics 2009-10-31 G. Parisi , M. Picco , F. Ritort

Use of dedicated computers in spin glass simulations allows one to equilibrate very large samples (of size as large as $L=32$) and to carry out "computer experiments" that can be compared to (and analyzed in combination with) laboratory…

Disordered Systems and Neural Networks · Physics 2022-10-12 V. Martin-Mayor , J. J. Ruiz-Lorenzo , B. Seoane , A. P. Young

Results of Monte Carlo simulations of the one-dimensional long-range Ising spin glass with power-law interactions in the presence of a (random) field are presented. By tuning the exponent of the power-law interactions, we are able to scan…

Disordered Systems and Neural Networks · Physics 2007-05-23 Helmut G. Katzgraber , A. P. Young

We introduce a novel method for numerical spin glass investigations: Simulations of two replica at fixed temperature, weighted such that a broad distribution of the Parisi overlap parameter $q$ is achieved. Canonical expectation values for…

Condensed Matter · Physics 2009-01-23 Bernd A. Berg , Wolfhard Janke

The stability of the spin-glass phase against a magnetic field is studied in the three and four dimensional Edwards-Anderson Ising spin glasses. Effective couplings and effective fields associated with length scale L are measured by a…

Disordered Systems and Neural Networks · Physics 2009-11-13 M. Sasaki , K. Hukushima , H. Yoshino , H. Takayama

We analyse the competition between spin glass (SG) order and local pairing superconductivity (SC) in the fermionic Ising spin glass with frustrated fermionic spin interaction and nonrandom attractive interaction. The phase diagram is…

Condensed Matter · Physics 2009-10-31 H. Feldmann , R. Oppermann

We study the quantum transition at $T=0$ in the spin-$\frac12$ Ising spin--glass in a transverse field in two dimensions. The world line path integral representation of this model corresponds to an effective classical system in (2+1)…

Condensed Matter · Physics 2009-10-22 Heiko Rieger , A. Peter Young

We determine the phase transition of the Levy spin glass. A regularized model where the coupling constants smaller than some cutoff $\epsilon$ are neglected can be studied by the cavity method for diluted spin glasses. We show how to handle…

Disordered Systems and Neural Networks · Physics 2015-05-14 K. Janzen , A. Engel , M. Mézard

We use Monte Carlo simulations to study the one-dimensional long-range diluted Heisenberg spin glass with interactions that fall as a power, sigma, of the distance. Varying the power is argued to be equivalent to varying the space dimension…

Disordered Systems and Neural Networks · Physics 2013-05-29 Auditya Sharma , A. P. Young

We study a p-spin spin-glass model to understand if the finite-temperature glass transition found in the mean-field regime of p-spin models, and used to model the behavior of structural glasses, persists in the non-mean-field regime. By…

Disordered Systems and Neural Networks · Physics 2010-02-18 Derek Larson , Helmut G. Katzgraber , M. A. Moore , A. P. Young

We point out a possibility of the weak universality of spin-glass phase transitions in three dimensions. The Ising, the XY, and the Heisenberg models with $\pm J$ bond distributions undergo finite-temperature phase transitions with a ratio…

Disordered Systems and Neural Networks · Physics 2007-05-23 Tota Nakamura , Shin-ichi Endoh , Takeo Yamamoto

We study the spectrum of the Hessian of the Sherrington-Kirkpatrick model near T=0, whose eigenvalues are the masses of the bare propagators in the expansion around the mean-field solution. In the limit $T\ll 1$ two regions can be…

Disordered Systems and Neural Networks · Physics 2011-02-28 A. Crisanti , C. De Dominicis

We study the phase transition of the $\pm J$ Heisenberg model in three dimensions. Using a dynamical simulation method that removes a drift of the system, the existence of the spin-glass (SG) phase at low temperatures is suggested. The…

Disordered Systems and Neural Networks · Physics 2007-05-23 F. Matsubara , T. Shirakura , S. Endoh

By quenched-randomly mixing local units of different spatial dimensionalities, we have studied Ising spin-glass systems on hierarchical lattices continuously in dimensionalities 1 =< d =< 3. The global phase diagram in temperature,…

Statistical Mechanics · Physics 2018-10-24 Bora Atalay , A. Nihat Berker

The spin-glass transition in a field in finite dimension is analyzed directly at zero temperature using a perturbative loop expansion around the Bethe lattice solution. The loop expansion is generated by the $M$-layer construction whose…

Disordered Systems and Neural Networks · Physics 2022-03-18 Maria Chiara Angelini , Carlo Lucibello , Giorgio Parisi , Gianmarco Perrupato , Federico Ricci-Tersenghi , Tommaso Rizzo

We have studied low-lying metastable states of the $\pm J$ Heisenberg model in two ($d=2$) and three ($d=3$) dimensions having developed a hybrid genetic algorithm. We have found a strong evidence of the occurrence of the Parisi states in…

Disordered Systems and Neural Networks · Physics 2009-11-10 F. Matsubara , T. Shirakura , Y. Baba

We study how the ground state of the two-dimensional Ising spin glass with Gaussian interactions in zero magnetic field changes on altering the boundary conditions. The probability that relative spin orientations change in a region far from…

Disordered Systems and Neural Networks · Physics 2009-10-31 Matteo Palassini , A. P. Young

We study in detail the quantum Sherrington-Kirkpatrick (SK) model, i.e. the infinite-range Ising spin glass in a transverse field, by solving numerically the effective one-dimensional model that the quantum SK model can be mapped to in the…

Statistical Mechanics · Physics 2017-09-20 A. P. Young

We prove the existence of one-step replica symmetry breaking (1RSB) for the mean field Ising spin glasses at finite temperature and identify the first critical temperature in Gardner transition. Specifically, Gardner conjectured that for…

Probability · Mathematics 2024-09-11 Yuxin Zhou

The occurrence of parity-time reversal ($\mathcal{PT}$) symmetry breaking is discussed in a non-Hermitian spin chain. The Hermiticity of the model is broken by the presence of an alternating, imaginary, transverse magnetic field. A full…

Quantum Physics · Physics 2010-08-25 Gian Luca Giorgi