Large-scale Monte Carlo simulations of the three-dimensional XY spin glass (2008)
We study the XY spin glass by large-scale Monte Carlo simulations for sizes up to 24^3, down to temperatures below the transition temperature found in earlier work. The data for the larger sizes show...
Size dependence of the minimum excitation gap in the Quantum Adiabatic Algorithm (2008)
Young, A. P., Knysh, S., Smelyanskiy, V. N.
We study the minimum gap in the quantum version of the Exact Cover problem using Quantum Monte Carlo simulations, with a view to understanding the complexity of the quantum adiabatic algorithm for...
New Insights from One-Dimensional Spin Glasses (2008)
Katzgraber, Helmut G., Hartmann, Alexander K., Young, A. P.
The concept of replica symmetry breaking found in the solution of the mean-field Sherrington-Kirkpatrick spin-glass model has been applied to a variety of problems in science ranging from biological...
Large-scale Monte Carlo simulations of the isotropic three-dimensional Heisenberg spin glass (2007)
We study the Heisenberg spin glass by large-scale Monte Carlo simulations for sizes up to 32^3, down to temperatures below the transition temperature claimed in earlier work. The data for the larger...
Critical behavior of the three- and ten-state short-range Potts glass: A Monte Carlo study (2006)
Lee, L. W., Katzgraber, Helmut G., Young, A. P.
We study the critical behavior of the short-range p-state Potts spin glass in three and four dimensions using Monte Carlo simulations. In three dimensions, for p = 3, a finite-size scaling analysis...
Universality in three-dimensional Ising spin glasses: A Monte Carlo study (2006)
Katzgraber, Helmut G., Koerner, Mathias, Young, A. P.
We study universality in three-dimensional Ising spin glasses by large-scale Monte Carlo simulations of the Edwards-Anderson Ising spin glass for several choices of bond distributions, with...
Cepas, O., Young, A. P., Shastry, B. S.
We show that a continuous set of degenerate critical soft modes strongly enhances the first-order character of a fluctuation-induced first-order transition in the pyrochlore dipolar Heisenberg...
Probing the Almeida-Thouless line away from the mean-field model (2005)
Katzgraber, Helmut G., Young, A. P.
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...
Defect energy of infinite-component vector spin glasses (2005)
We compute numerically the zero temperature defect energy, Delta E, of the vector spin glass in the limit of an infinite number of spin components m, for a range of dimensions 2
Spin glasses in the limit of an infinite number of spin components (2005)
Lee, L.W., Dhar, Abhishek, Young, A.P.
We consider spin glass models in which the number of spin components m is infinite. In the formulation of the problem appropriate for numerical calculations proposed by several authors, we show that...
Temperature Cycles in the Heisenberg Spin Glass (2005)
Berthier, Ludovic, Young, A. P.
We study numerically the nonequilibrium dynamics of the three-dimensional Heisenberg Edwards-Anderson spin glass submitted to protocols during which temperature is shifted or cycled within the spin...
Finite size scaling of the correlation length above the upper critical dimension (2004)
We show numerically that correlation length at the critical point in the five-dimensional Ising model varies with system size L as L^{5/4}, rather than proportional to L as in standard finite size...
Free energies in the presence of electric and magnetic fields (2004)
Narayan, Onuttom, Young, A. P.
We discuss different free energies for materials in static electric and magnetic fields. We explain what the corresponding Hamiltonians are, and describe which choice gives rise to which result for...
Spin glasses in the limit of an infinite number of spin components (2004)
Lee, L. W., Dhar, A., Young, A. P.
We consider the spin glass model in which the number of spin components, m, is infinite. In the formulation of the problem appropriate for numerical calculations proposed by several authors, we show...
Absence of an Almeida-Thouless line in Three-Dimensional Spin Glasses (2004)
Young, A. P., Katzgraber, Helmut G.
We present results of Monte Carlo simulations of the three-dimensional Edwards-Anderson Ising spin glass in the presence of a (random) field. A finite-size scaling analysis of the correlation length...
Correlation Length of the Two-Dimensional Ising Spin Glass with Gaussian Interactions (2004)
Katzgraber, Helmut G., Lee, L. W., Young, A. P.
We study the correlation length of the two-dimensional Ising spin glass with a Gaussian distribution of interactions, using an efficient Monte Carlo algorithm proposed by Houdayer, that allows larger...
Aging Dynamics of the Heisenberg Spin Glass (2003)
We numerically study the non-equilibrium dynamics of the three dimensional Heisenberg Edwards-Anderson spin glass following a sudden quench to its low temperature phase. The subsequent aging behavior...
Time and length scales in spin glasses (2003)
Berthier, Ludovic, Young, A. P.
We discuss the slow, nonequilibrium, dynamics of spin glasses in their glassy phase. We briefly review the present theoretical understanding of the spectacular phenomena observed in experiments and...
Lack of Ultrametricity in the Low-Temperature phase of 3D Ising Spin Glasses (2003)
Hed, Guy, Young, A. P., Domany, Eytan
We study the low-temperature spin-glass phases of the Sherrington-Kirkpatrick (SK) model and of the 3-dimensional short range Ising spin glass (3dISG). For the SK model, evidence for ultrametricity...
Ensemble dependence in the random transverse-field Ising chain (2003)
In a disordered system one can either consider a microcanonical ensemble, where there is a precise constraint on the random variables, or a canonical ensemble where the variables are chosen according...
Katzgraber, Helmut G., Young, A. P.
Results are presented for the geometry of low-energy excitations in the one-dimensional Ising spin chain with power-law interactions, in which the model parameters are chosen to yield a finite...
Ensemble dependence in the Random transverse-field Ising chain (2003)
In a disordered system one can either consider a microcanonical ensemble, where there is a precise constraint on the random variables, or a canonical ensemble where the variables are chosen according...
Energetics of clusters in the two-dimensional Ising spin glass (2003)
Berthier, Ludovic, Young, A. P.
We study numerically the properties of local low-energy excitations in the two-dimensional Ising spin glass. Given the ground state, we determine the lowest-lying connected cluster of flipped spins...
Single spin- and chiral-glass transition in vector spin glasses in three-dimensions (2003)
Results of Monte Carlo simulations of XY and Heisenberg spin glass models in three dimensions are presented. A finite size scaling analysis of the correlation length of the spins and chiralities of...
Low Energy Excitations in Spin Glasses from Exact Ground States (2002)
Palassini, Matteo, Liers, Frauke, Juenger, Michael, Young, A. P.
We investigate the nature of the low-energy, large-scale excitations in the three-dimensional Edwards-Anderson Ising spin glass with Gaussian couplings and free boundary conditions, by studying the...
Monte Carlo studies of the one-dimensional Ising spin glass with power-law interactions (2002)
Katzgraber, H. G., Young, A. P.
We present results from Monte Carlo simulations of the one-dimensional Ising spin glass with power-law interactions at low temperature, using the parallel tempering Monte Carlo method. For a set of...
Interface energies in Ising spin glasses (2002)
Aspelmeier, T., Moore, M. A., Young, A. P.
The replica method has been used to calculate the interface free energy associated with the change from periodic to anti-periodic boundary conditions in finite-dimensional spin glasses. At mean-field...
Hartmann, Alexander K., Bray, Alan J., Carter, A. C., Moore, M. A., Young, A. P.
We study the scaling behavior of domain-wall energies in two-dimensional Ising spin glasses with Gaussian and bimodal distributions of the interactions and different types of boundary conditions. The...
Large-Scale, Low-Energy Excitations in the Two-Dimensional Ising Spin Glass (2002)
We study large-scale, low-energy excitations in the Ising spin glass with Gaussian interactions in two-dimensions at zero temperature, using an optimization algorithm to determine exact ground...
Numerical studies of the two- and three-dimensional gauge glass at low temperature (2002)
Katzgraber, Helmut G., Young, A. P.
We present results from Monte Carlo simulations of the two- and three-dimensional gauge glass at low temperature using the parallel tempering Monte Carlo method. Our results in two dimensions...
We study the dynamics of the q-state random bond Potts ferromagnet on the square lattice at its critical point by Monte Carlo simulations with single spin-flip dynamics. We concentrate on q=3 and...
Katzgraber, Helmut G., Young, A. P.
We present results of Monte Carlo simulations, using parallel tempering, on the three- and four-dimensional Edwards-Anderson Ising spin glass with Gaussian couplings at low temperatures with free...
Monte Carlo simulations of the four-dimensional XY spin glass at low temperatures (2001)
Katzgraber, Helmut G., Young, A. P.
We report results for simulations of the four-dimensional XY spin glass using the parallel tempering Monte Carlo method at low temperatures for moderate sizes. Our results are qualitatively...
Spin Glasses: A Computational Challenge for the 21st Century (2001)
I discuss the computational challenges of the spin glass problem, and illustrate them with two examples from my recent work. I.
Numerical Studies of Spin Glass Problems in Magnetism and Superconductivity (2001)
I will describe spin glass ideas as applied to magnetism and superconductivity, concentrating on numerical studies. The existence of a phase transition will be shown and some open problems discussed....
Lower Critical Dimension of Ising Spin Glasses (2001)
Exact ground states of two-dimensional Ising spin glasses with Gaussian and bimodal (+- J) distributions of the disorder are calculated using a ``matching'' algorithm, which allows large system sizes...
Specific-Heat Exponent of Random-Field Systems via Ground-State Calculations (2001)
Exact ground states of three-dimensional random field Ising magnets (RFIM) with Gaussian distribution of the disorder are calculated using graph-theoretical algorithms. Systems for different...
Nature of the Spin-glass State in the Three-dimensional Gauge Glass (2001)
Katzgraber, Helmut G., Young, A. P.
We present results from simulations of the gauge glass model in three dimensions using the parallel tempering Monte Carlo technique. Critical fluctuations should not affect the data since we...
State Hierarchy Induced by Correlated Spin Domains in short range spin glasses (2001)
Domany, Eytan, Hed, Guy, Palassini, Matteo, Young, A. P.
We generate equilibrium configurations for the three and four dimensional Ising spin glass with Gaussian distributed couplings at temperatures well below the transition temperature T_c. These states...
Reply to Comment on "Nature of Spin Glass State" (2000)
Palassini, Matteo, Young, A. P.
This is a reply to cond-mat/0010033 by Newman and Stein, which is a comment on on our paper Phys. Rev. Lett. 85, 3017 (2000), cond-mat/0002134.
The +/-J Spin Glass: Effects of Ground State Degeneracy (2000)
Palassini, Matteo, Young, A. P.
We perform Monte Carlo simulations of the Ising spin glass at low temperature in three dimensions with a +/-J distribution of couplings. Our results display crossover scaling between T=0 behavior,...
Computer Science in Physics (2000)
This talk describes how techniques developed by Computer Scientists have helped our understanding of certain problems in statistical physics which involve randomness and ``frustration''. Examples...
Computer Science in Physics (2000)
. This talk describes how techniques developed by Computer Scientists have helped our understanding of certain problems in statistical physics which involve randomness and "frustration". Examples...
Convergence of Monte Carlo Simulations to Equilibrium (2000)
Narayan, Onuttom, Young, A. P.
We give two direct, elementary proofs that a Monte Carlo simulation converges to equilibrium provided that appropriate conditions are satisfied. The first proof requires detailed balance while the...
Monte Carlo Simulations of Spin Glasses at Low Temperatures (2000)
Katzgraber, Helmut G., Palassini, Matteo, Young, A. P.
We report the results of Monte Carlo simulations on several spin glass models at low temperatures. By using the parallel tempering (Exchange Monte Carlo) technique we are able to equilibrate down to...
Reply to Comment on "Triviality of the Ground State Structure in Ising Spin Glasses" (2000)
Palassini, Matteo, Young, A. P.
We reply to the comment of Marinari and Parisi [cond-mat/0002457 v2] on our paper [Phys. Rev. Lett. 83, 5126 (1999) and cond-mat/9906323]. We show that the data in the comment are affected by strong...
Nature of the Spin Glass State (2000)
Palassini, Matteo, Young, A. P.
The nature of the spin glass state is investigated by studying changes to the ground state when a weak perturbation is applied to the bulk of the system. We consider short range models in three and...
Slow Dynamics At Quantum Phase Transitions (1999)
This paper discusses how slow dynamics can occur in the vicinity of quantum phase
Finite Temperature Ordering in the Three-Dimensional Gauge Glass (1999)
We present results of Monte Carlo simulations of the gauge glass model in three dimensions using exchange Monte Carlo. We show for the first time clear evidence of the vortex glass ordered phase at...
Ground State Structure of Spin Glasses (1999)
Palassini, Matteo, Young, A. P.
We investigate the ground state structure of Ising spin glasses in zero magnetic field by determining how the ground state changes in a fixed finite block far from the boundaries when the boundary...
Triviality of the Ground State Structure in Ising Spin Glasses (1999)
Palassini, Matteo, Young, A. P.
We investigate the ground state structure of the three-dimensional Ising spin glass in zero field by determining how the ground state changes in a fixed finite block far from the boundaries when the...
Trivial Ground State Structure in the Two-Dimensional Ising Spin Glass (1999)
Palassini, Matteo, Young, A. P.
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...
Monte Carlo Study of the Critical Behavior of Random Bond Potts Models (1999)
We present results of Monte Carlo simulations of random bond Potts models in two dimensions, for different numbers of Potts states, q. We introduce a simple scheme which yields continuous self-dual...
Pich, C., Young, A. P., Rieger, H., Kawashima, N.
We study the quantum phase transition in the two-dimensional random Ising model in a transverse field by Monte Carlo simulations. We find results similar to those known analytically in one-dimension....
HIGH-PRESSURE RESEARCH TOWARD HIGH-ENERGY PROPELLANTS. (1998)
Sclar,C. B., Krause,H. H., Carrison,L. C., Young,A. P., Brasch,J. W.
An experimental program was carried out on specific materials to determine the feasibility of utilizing high pressure to synthesize high-energy propellants. Pressurization experiments were conducted...
ON THE HIGH-PRESSURE FORM OF FEVO4, (1998)
Laves,F., Young,A. P., Schwartz,C. M.
Evidence is presented that the atomic arrangement of high-pressure FeVO4 is similar to that of ambientpressure FeNbO4. Evidence is presented in the form of comparing the indexing of high-pressure...
Dynamical Critical Properties of the Random Transverse-Field Ising Spin Chain (1998)
We study the dynamical properties of the random transverse-field Ising chain at criticality using a mapping to free fermions, with which we can obtain numerically exact results for system sizes, L,...
Fisher, Daniel S., Young, A. P.
A previously introduced real space renormalization-group treatment of the random transverse-field Ising spin chain is extended to provide detailed information on the distribution of the energy gap...
Critical Behavior of the Two-Dimensional Random Quantum Ising Ferromagnet (1998)
We study the quantum phase transition in the two-dimensional random Ising model in a transverse field by Monte Carlo simulations. We find results similar to those known analytically in one-dimension:...
Dynamical universality classes of the superconducting phase transition (1997)
Lidmar, Jack, Wallin, Mats, Wengel, Carsten, Girvin, S. M., Young, A. P.
We present a finite temperature Monte Carlo study of the XY-model in the vortex representation, and study its dynamical critical behavior in two limits. The first neglects magnetic field...
Finite Temperature and Dynamical Properties of the Random Transverse-Field Ising Spin Chain (1997)
We study numerically the paramagnetic phase of the spin-1/2 random transverse-field Ising chain, using a mapping to non-interacting fermions. We extend our earlier work, Phys. Rev. 53, 8486 (1996),...
The recently proposed state of a disordered type-II superconductor in a magnetic field, the "vortex glass", is discussed and compared with the "spin glass" transition in magnetic systems. We discuss...
Introduction Spin glasses are random magnetic systems, where the disorder is sufficiently severe that one has "frustration", i.e. no spin configuration simultaneously minimizes each term in the...
Phase Transitions in Random Systems (1997)
. These lectures discuss the theory of phase transitions and critical phenomena in random systems. First a discussion is given of the basic principles, including averaging, the concept of...
Numerical Simulations of Quantum Phase Transitions (1997)
In this talk I will describe some examples of quantum phase transitions with disorder and explain in what ways these transitions differ from conventional phase transitions at finite temperature. It...
Current-Voltage Characteristics of Two-Dimensional Vortex Glass Models (1997)
R. A. Hyman, Mats Wallin, S. M. Girvin, A. P. Young
We have performed Monte Carlo simulations to determine current--voltage characteristics of two vortex glass models in two dimensions. Our results confirm earlier studies which concluded that there is...
Two-Dimensional Superfluids (1997)
. These lectures describe the behaviour of two-dimensional superfluids, which differ from three-dimensional systems in having phase transitions driven by thermally excited vortices. Firstly, I will...
Finite temperature properties of the Spin- (1997)
this paper we investigate the spin-
Bosons in a Random Potential (1997)
INTRODUCTION Most studies of phase transitions have concentrated on systems where the transition is driven by a change in temperature, i.e. starting from an ordered state at low temperature, thermal...
Quantum Phase Transitions (1997)
INTRODUCTION Lattice gauge theorists usually study what I am calling here "quantum" phase transitions, i.e. phase transitions driven by quantum, rather than thermal, fluctuations. In condensed matter...
Low temperature relaxational dynamics of the Ising chain in a transverse field (1996)
We present asymptotically exact results for the real time order parameter correlations of a class of d=1 Ising models in a transverse field at low temperatures (T) on both sides of the quantum...
Ising spin glasses in a transverse field exhibit a zero temperature quantum phase transition, which is driven by quantum rather than thermal fluctuations. They constitute a universality class that is...
Monte Carlo Study of a Three-Dimensional Vortex Glass Model with Screening (1996)
We investigate the critical behavior of the gauge glass model for the vortex glass transition in three-dimensional superconductors, including screening of the interaction between vortices. A Monte...
Griffiths Singularities in the Disordered Phase of a Quantum Ising Spin Glass (1995)
We study a model for a quantum Ising spin glass in two space dimensions by Monte Carlo simulations. In the disordered phase at $T=0$, we find power law distributions of the local susceptibility and...
Study of Chirality in the Two-Dimensional XY Spin Glass (1995)
We study the chirality in the Villain form of the XY spin glass in two--dimensions by Monte Carlo simulations. We calculate the chiral-glass correlation length exponent $\nu_{\scriptscriptstyle CG}$...
A Numerical Study of the Random Transverse-Field Ising Spin Chain (1995)
We study numerically the critical region and the disordered phase of the random transverse-field Ising chain. By using a mapping of Lieb, Schultz and Mattis to non-interacting fermions, we can obtain...
Phase Transition in the Three-Dimensional $\pm J$ Ising Spin Glass (1995)
We have studied the three-dimensional Ising spin glass with a $\pm J$ distribution by Monte Carlo simulations. Using larger sizes and much better statistics than in earlier work, a finite size...
Current--Voltage Characteristics of Two--Dimensional Vortex Glass Models (1994)
Hyman, R. A., Wallin, M., Fisher, M. P. A., Girvin, S. M., Young, A. P.
We have performed Monte Carlo simulations to determine current--voltage characteristics of two different vortex glass models in two dimensions. The results confirm the conclusions of earlier studies...
Absence of a Phase Transition in a Three--Dimensional Vortex Glass Model with Screening (1994)
We study the gauge glass model for the vortex glass transition in type--II superconductors, including screening of the interaction between vortices. {}From the size dependence of the domain wall...
For the spin-$\frac{1}{2}$ Heisenberg antiferromagnet on the Kagom\'e lattice we calculate the high temperature series for the specific heat and the structure factor. A comparison of the series with...
Monte Carlo study of a vortex glass model (1993)
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...
The superconductor-insulator transition in 2D dirty boson systems (1993)
Wallin, M., Sorensen, E., Girvin, S. M., Young, A. P.
Universal properties of the zero temperature superconductor-insulator transition in two-dimensional amorphous films are studied by extensive Monte Carlo simulations of bosons in a disordered medium....
Critical Exponents of the Three Dimensional Random Field Ising Model (1993)
The phase transition of the three--dimensional random field Ising model with a discrete ($\pm h$) field distribution is investigated by extensive Monte Carlo simulations. Values of the critical...
Critical Exponents of the Three Dimensional Random Field Ising Model (1993)
The phase transition of the three--dimensional random field Ising model with a discrete ($\pm h$) field distribution is investigated by extensive Monte Carlo simulations. Values of the critical...
Plastic deformation of aluminum single crystals at elevated temperatures (1956)
R. D. Johnson, A. P. Young, A. D. Schwope
This report describes the results of a comprehensive study of plastic deformation of aluminum single crystals over a wide range of temperatures. The results of constant-stress creep tests have been...
Plastic deformation of aluminum single crystals at elevated temperatures (1955)
R. D. Johnson, A. P. Young, A. D. Schwope
This report describes the results of a comprehensive study of plastic deformation of aluminum single crystals over a wide range of temperatures. The results of constant-stress creep tests have been...
Xie, J, Roddy, P, Rife, T K, Murad, F, Young, A P
In this report we demonstrate that the human cerebellum contains neuronal nitric oxide synthase (nNOS) mRNAs with two distinct 5'-untranslated regions that are encoded through use of closely linked...