A Monte Carlo Study of the Specific Heat of Diluted Antiferromagnets
|
|
- Rodger Edwards
- 6 years ago
- Views:
Transcription
1 A Monte Carlo Study of the Specific Heat of Diluted Antiferromagnets M. Staats and K. D. Usadel Theoretische Physik and SFB 166 Gerhard-Mercator-Universität Gesamthochschule Duisburg Duisburg, Germany Abstract The -dimensional diluted antiferromagnet in a magnetic field has a longe-range ordered state for sufficiently low temperatures and external fields. We study the irreversibilities at the phase transition from this state into the paramagnetic state at higher temperatures. Performing field cooling and zero field cooling simulation procedures we find a small irreversibility in the internal energy and the specific heat, although the behavior of the order parameter is irreversible and the phase transition is suppressed in the FC case. The specific heat shows a non-critical broad maximum above the transition temperature Tc. The results are compatible with recent experimental results obtained by Satooka et. al., whereas our interpretation ofthedataisdifferent. Keywords: Critical-point effects, specific heats, short-range order, Numerical simulation studies, Spin-glass and other random models
2 ii 1 Introduction The behavior of diluted antiferromagnets in a field (DAFF) is of both theoretical and experimental interest. The DAFF is expected to be in the same universality class as the Random Field Ising Model (RFIM) [1, ], or at least as the RFIM with a Gaussian distribution of the random fields [, 4]. For sufficiently low temperatures below a critical temperature T c (B) and external fields lower than a critical B c the system is in a long-range ordered antiferromagnetic state [5, 6]. When increasing the temperature, a phase transition into a paramagnetic state occurs at T c (B). Up to now, the nature of this phase transition is not completely understood, and the question of the universality class of the DAFF is not finally settled. Also, the value and even the sign of the critical exponent for the specific heat is not known. Experiments usually yield a positive or 0 [7, 8], whereas in simulations and other numerical works is negative [9, 10]. While, as shown in this work, it is possible to analyze simulation data of the order parameter with finite size scaling as in ordinary second order phase transitions, the experimental situation is not clear, e. g. concentration gradients of the dilution in the measured sample may influence the critical behavior and leave room for a wide range of interpretations. It is well known that because of the strong disorder in such systems equilibrium is not reached when cooling the system in an external field from the paramagnetic state. This is called the field cooling (FC) procedure. On the other hand, if the system is in the ground state at low temperatures, one can expect to measure equilibrium behavior when heating the system. In experiments this is done by first cooling the system in zero field (ZFC), so that the ordered antiferromagnetic state is reached before the external field is switched on. In simulations it is easy to prepare the system in such an antiferromagnetically ordered state. Since FC and ZFC procedures are well distinguished, it is no surprise that in general there are differences in physical observables between both cases, i. e. that there are irreversibilities. This is found in experiments [11] as well in simulations [1, 1]. In contrast to quantities like the magnetization or the staggered magnetization (antiferromagnetic order parameter), recent experiments [14, 15] find, that surprisingly there are no irreversibilities for the specific heat, or at least, that they are very small [8]. These experimental findings are the motivation of this work, in which we investigate the equilibrium and non-equilibrium (hysteresis) behavior of the specific heat in FC and ZFC procedures with Monte Carlo techniques.
3 iii Model and Simulation To study the thermal phase transition in the DAFF, we simulate a threedimensional diluted antiferromagnet in an external field using Monte Carlo methods. The Ising-Hamiltonian is given by H =,J X hiji " i " j i j, B X i " i i ; (1) where the summation hiji runs over the nearest neighbor interactions in a simple cubic lattice. The coupling constant J is set to,1. The dilution is introduced through the quenched variables " i, which are 0 with a probability p and 1 otherwise. For all simulations in this work p is set to 0:5, which is well above the percolation threshold. We set the external field fixed to a value of B = 0:8, which is large enough to show all the irreversibilities which are observed in experiments and other simulations, but which is not too large so that the ground state is still long range ordered. Periodic boundary conditions are used. We study the phase transition by simulating heating-cooling cycles of the system, corresponding to ZFC and FC measurements. At T = 0 the system is prepared in the antiferromagnetically ordered ground state. Then the temperature is increased in temperature dependent steps. For each temperature we performed Monte Carlo Steps, if not mentioned otherwise. When the maximum temperature of our simulation is reached, we initialize the system with a random spin configuration, corresponding to infinite temperature. This is done to destroy any remaining correlations in the system. After that, the system is cooled down the same way it was heated. To study the equilibrium behavior we used the Swendsen-Wang cluster algorithm [16]. The coupling to the external field was taken into account via applying the heat-bath switching probability computed from the magnetization of the clusters. For a realistic simulation of the irreversibilities at the phase transition, we used Glauber dynamics (heat-bath algorithm), which is believed to reproduce the dynamics of the experimental system. We simulated systems with of size 5 ; 50 ; 100 and 160 with the single spin flip algorithm and 0 ; 0 ; 40 and 56 with the cluster algorithm.
4 iv Results.1 Equilibrium behavior First we are interested in the equilibrium behavior at the phase transition. Our aim is to determine the critical temperature T c for our given set of parameters using finite size scaling techniques. Therefore, we only analyzed the ZFC data, as it is widely accepted, that they show the phase transition from the ordered state into the paramagnetic state, which is generally doubted for the FC data. We used the Swendsen-Wang algorithm to obtain the data, since non-equilibrium effects are much smaller with this algorithm compared to a single spin flip algorithm. This can be seen from a comparison of the specific heat obtained either from the calculated internal energy c = [@U=@T] av, or by calculating the energy fluctuations c = N=T [hu i,hui ] av,wheren is the number of spins in the system, hi denotes the thermal, and [] av the configurational average. Only very small differences in both quantities are obtained when using the Swendsen-Wang algorithm. M st L = L = 0 L = 0 L = 40 L = (T, T c ) L 1= Figure 1 Figure 1: Scaling Plot of the ZFC data for the antiferromagnetic order parameter M st To determine the critical temperature T c we use finite size scaling anal-
5 v ysis for both the staggered magnetization M st and the disconnected susceptibility dis = N P 1 N ih i i. The finite size scaling relations (see av e. g. [17]) for the staggered magnetization M st;l and the disconnected susceptibility dis;l of finite systems with size L are given by M st;l = L,= ~ M st (T, T c )L 1= () dis;l = L = ~ dis (T, T c )L 1= : () From a scaling analysis of both M st and dis we obtain the transition temperature T c 1:5 0:05 and the critical exponents 1:09 0:05 (correlation length), 0:15 0:0 (order parameter), and :9 0:1. These exponents fulfill the modified hyper-scaling equation d =. Because of the limited range of system sizes we do not claim to improve the values of critical exponents for the DAFF. Nevertheless, our values of and are in agreement with other results [18, 9, 4], whereas our result for turns out to be larger than previous results. The scaling plot for M st is shown in Figure 1. The scaling plot for dis is of similar quality and is therefore not shown. Figure shows the equilibrium behavior of the specific heat, the inset shows the specific heat for several system sizes. The specific heat show a broad maximum, which occurs at temperatures well above the critical temperature T c.. Irreversibilities Irreversible behavior as observed in experiments is also found in simulations, but it is important to note that this may depend on the algorithm used. To compare with experiments one therefore has to use an algorithm which reflects the dynamics of the experimental system. It is widely agreed that this is achieved by using the single spin flip algorithm with random updates (Glauber dynamics). With this algorithm we analyzed the order parameter M st, the internal energy U and the specific heat c, to compare our data with experiments. Figure shows the order parameter for various system sizes in ZFC- FC loops. In agreement with other works (e. g. [1]) we find that the order parameter will not increase at T c when cooling the system in an external field. This indicates that the phase transition is suppressed and the system is frozen in a domain state. The non-zero value for M st below T c in our
6 vi 0.7 c pl (hu i,huihu T Figure Figure : The ZFC data for the specific heat for a system size L = 0 calculated with two different methods. The vertical line is drawn at T c.the inset shows the specific heat for several system sizes (L =0; 0; 40; 56). simulations can be clearly identified as a finite size effect, since the larger the systems are, the smaller the order parameter after the FC. The internal energy for a ZFC-FC cycle is shown in figure 4a. In contrast to the order parameter and the magnetization (see [11, 1]), there is only a small split between the ZFC an FC curves of the internal energy. This behavior is reflected in the specific heat c. Apart from a small region around T c there is no difference between the ZFC and FC curves (figure 4b). 4 Discussion We have shown that the specific heat has a broad maximum and shows only very little hysteresis as compared for instance to the order parameter. This surprising result has also been seen in experiments [14, 15]. The critical temperature T c clearly lies below the maximum of the specific heat. This is not a finite size effect, since the position of the maximum is practically independent of system size. We conclude that the broad maximum of the specific heat has nothing to do with critical behavior. Note that the
7 vii M st ZFC L = FC L = ZFC L = FC L = 50 ZFC L = FC L = 100? 44 ZFC L = FC L = ??????????? 0.1???????????????????????? ??????? 4? T Figure Figure : The order parameter M st loop for several systems sizes in a ZFC-FC U a) ZFC FC c (ZFC) (FC) T Figure 4 Figure 4: ZFC-FC cycles: a) The internal energy b) The specific heat
8 viii true T c may be lower than the one we determined from finite size scaling. A more elaborate analysis only would yield an even lower T c, because we are heating the system from the long range ordered phase and the order parameter has to go to zero at T c. Thus, longer simulations can only result in a decay of the order parameter at lower temperatures. An still open question is the critical behavior of the specific heat of the DAFF and the RFIM. The existence of irreversibilities in experiments is still unclear and experimental and theoretical values for the critical exponent do not agree [7, 8, 9, 10]. We have shown that the broad maximum does not correspond to critical behavior, by showing that the critical temperature lies on the left of the maximum of the specific heat and that there is no size dependence of its position. This opens new questions on how to interpret experimental data of the DAFF. Although the DAFF is in the same universality class as the RFIM with Gaussian random fields, the critical behavior of the DAFF is covered by the broad, non-critical peak, whereas in the RFIM the critical behavior of the specific heat can be measured [9]. It could be possible that the same effect occurs in experiments which measure the specific heat directly. The experimental data can be reproduced in the sense, that, although there has to be a small hysteresis in ZFC-FC loops, as indicated by the split in the internal energy, this hysteresis will be very small and difficult to measure. Our results are in contradiction with the interpretation of experimental data in [15], where it was claimed that the critical behavior is also present in the FC procedure. Our measurements of the order parameter clearly indicate that the phase transition is suppressed when cooling the system in an external field. It is expected that detailed analysis in the region around T c will show, that the equilibrium specific heat develops a singularity at T c in the ZFC case, i. e. in equilibrium. The resolution obtained by our simulations does not allow a final answer to this question. We believe that a detailed analysis, which will of course be quite expensive in computing time, will reveal the same behavior as it has been found recently in two-dimensional diluted ferromagnets: A small critical peak at T c followed by a broad, noncritical maximum at higher temperatures [19]. Since the phase transition does not occur in the FC case, irreversibilities in the specific heat must exist, but obviously they are very small in both experiments and in simulations. Acknowledgment: We would like to thank U. Nowak and A. Hucht for helpful discussions. This work was in part supported by the Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 166.
9 ix References [1] S. Fishman and A. Aharony, J. Phys. C1(1979) L79. [] J.L.Cardy,Phys.Rev.B9 (1984) 505. [] J.-C. A. d Auriac and N. Sourlas, Europhys. Lett. 9 (1997) 47. [4] A. K. Hartmann and U. Nowak, Eur. Phys. J. B (1998) (accepted for publication). [5] J. Z. Imbrie, Phys. Rev. Lett. 5 (1984) [6] J. Bricmont and A. Kupiainen, Phys. Rev. Lett. 59 (1987) 189. [7] D.P.Belanger,A.R.King,V.Jaccarino,andJ.L.Cardy, Phys.Rev.B 8 (198) 5. [8] Z. Zlani c and D. P. Belanger, J. Magn. Magn. Mater. 186 (1998) 65. [9] H. Rieger, Phys. Rev. B 5 (1995) [10] U. Nowak, K. D. Usadel, and J. Esser, Physica A 50 (1998) 1. [11] F. C. Montenegro, A. R. King, V. Jaccarino, S.-J. Han, and D. P. Belanger, Phys. Rev. B 44 (1991) 155. [1] C. Ro, G. S. Grest, C. M. Soukulis, and K. Levin, Phys. Rev. B 1 (1985) 168. [1] U. Nowak and K. Usadel, Phys. Rev. B 9 (1989) 516. [14] R. J. Birgenau, J. Magn. Magn. Mater (1998) 1. [15] J. Satooka, H. A. Katori, A. Tobo, and K. Katsumata, Phys. Rev. Lett. 81 (1998) 709. [16] R. H. Swendsen and J.-S. Wang, Phys. Rev. Lett. 58 (1987) 86. [17] K. Binder and D. W. Heermann, Monte Carlo Simulation in Statistical Physics, Springer Series in Solid State Sciences, Springer, [18] A. T. Ogielski and I. Morgenstern, Phys. Rev. Lett. 54 (1985) 98. [19] W. Selke, L. N. Shchur, and O. A. Vasilyev, Physica A 59 (1998) 88.
Monte Carlo studies of slow relaxation in diluted antiferromagnets
Monte Carlo studies of slow relaxation in diluted antiferromagnets U. Nowak and K. D. Usadel Theoretische Physik and Sonderforschungsbereich No. 166, Universitiit-GH-Duisburg, Lotharstrasse 1, 4100 Duisburg,
More informationPhase transitions in the Potts spin-glass model
PHYSICAL REVIEW E VOLUME 58, NUMBER 3 SEPTEMBER 1998 Phase transitions in the Potts spin-glass model Giancarlo Franzese 1 and Antonio Coniglio 1,2 1 Dipartimento di Scienze Fisiche, Università di Napoli,
More informationMagnetization switching in a Heisenberg model for small ferromagnetic particles
Magnetization switching in a Heisenberg model for small ferromagnetic particles D. Hinzke and U. Nowak* Theoretische Tieftemperaturphysik, Gerhard-Mercator-Universität-Duisburg, D-47048 Duisburg, Germany
More informationPOWER-LAW CORRELATED PHASE IN RANDOM-FIELD XY MODELS AND RANDOMLY PINNED CHARGE-DENSITY WAVES Ronald Fisch Dept. of Physics Washington Univ. St. Louis, MO 63130 ABSTRACT: Monte Carlo simulations have been
More informationarxiv:cond-mat/ v2 [cond-mat.stat-mech] 2 Apr 1998
Nonequilibrium Phase Transition in the Kinetic Ising model: Dynamical symmetry breaking by randomly varying magnetic field arxiv:cond-mat/979v2 [cond-mat.stat-mech] 2 Apr 998 Muktish Acharyya Institute
More informationNumerical Analysis of 2-D Ising Model. Ishita Agarwal Masters in Physics (University of Bonn) 17 th March 2011
Numerical Analysis of 2-D Ising Model By Ishita Agarwal Masters in Physics (University of Bonn) 17 th March 2011 Contents Abstract Acknowledgment Introduction Computational techniques Numerical Analysis
More informationThe Bak-Tang-Wiesenfeld sandpile model around the upper critical dimension
Phys. Rev. E 56, 518 (1997. 518 The Bak-Tang-Wiesenfeld sandpile model around the upper critical dimension S. Lübeck and K. D. Usadel Theoretische Tieftemperaturphysik, Gerhard-Mercator-Universität Duisburg,
More informationSimulation of Magnetization Switching in Nanoparticle Systems
Simulation of Magnetization Switching in Nanoparticle Systems D. Hinzke and U. Nowak Theoretische Physik, Gerhard-Mercator-Universität 47048 Duisburg, Germany Pacs-numbers: 75.10.Hk; 75.40.Mg; 75.40.Gb
More informationSpin glass dynamics in RKKY interacting disordered magnetic system
Spin glass dynamics in RKKY interacting disordered magnetic system Zhang Kai-Cheng( 张开成 ) a) and Song Peng-Yun( 宋朋云 ) b) a) Department of Physics, Bohai University, Jinzhou 121013, China b) School of Science,
More informationarxiv: v3 [cond-mat.dis-nn] 20 May 2014
1 Analytical estimates of the locations of phase transition points in the ground state for the bimodal Ising spin glass model in two dimensions Chiaki Yamaguchi arxiv:1309.6554v3 [cond-mat.dis-nn] 20 May
More informationarxiv:cond-mat/ v1 13 May 1999
Numerical signs for a transition in the 2d Random Field Ising Model at T = 0 arxiv:cond-mat/9905188v1 13 May 1999 Carlos Frontera and Eduard Vives Departament d Estructura i Constituents de la Matèria,
More informationPhase Transitions in Relaxor Ferroelectrics
Phase Transitions in Relaxor Ferroelectrics Matthew Delgado December 13, 2005 Abstract This paper covers the properties of relaxor ferroelectrics and considers the transition from the paraelectric state
More informationarxiv: v3 [cond-mat.stat-mech] 14 Feb 2013
Dynamical Properties of Random Field Ising Model Suman Sinha Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 79, India Pradipta Kumar Mandal Department of Physics,
More informationWeak first-order transition in the three-dimensional site-diluted Ising antiferromagnet in a magnetic field
Weak first-order transition in the three-dimensional site-diluted Ising antiferromagnet in a magnetic field A. Maiorano,,2 V. Martín-Mayor, 3,2 J. J. Ruiz-Lorenzo,,2 and A. Tarancón 4,2 Departamento de
More informationThe Phase Transition of the 2D-Ising Model
The Phase Transition of the 2D-Ising Model Lilian Witthauer and Manuel Dieterle Summer Term 2007 Contents 1 2D-Ising Model 2 1.1 Calculation of the Physical Quantities............... 2 2 Location of the
More informationPhase transitions and finite-size scaling
Phase transitions and finite-size scaling Critical slowing down and cluster methods. Theory of phase transitions/ RNG Finite-size scaling Detailed treatment: Lectures on Phase Transitions and the Renormalization
More informationGraphical Representations and Cluster Algorithms
Graphical Representations and Cluster Algorithms Jon Machta University of Massachusetts Amherst Newton Institute, March 27, 2008 Outline Introduction to graphical representations and cluster algorithms
More informationarxiv:cond-mat/ v1 [cond-mat.stat-mech] 24 Jul 2001
Autocorrelation functions in 3D Fully Frustrated Systems arxiv:cond-mat/0107509v1 [cond-mat.stat-mech] 24 Jul 2001 G. Franzese a, A. Fierro a, A. De Candia a and A. Coniglio a,b Dipartimento di Scienze
More informationPROOF COPY [LW7657E] PRE
PHYSICAL REVIEW E, VOLUME 63, 0561XX Susceptibility and percolation in two-dimensional random field Ising magnets E. T. Seppälä and M. J. Alava Laboratory of Physics, Helsinki University of Technology,
More informationThickness Dependence of Magnetic Hysteresis of Ising Films in Nano-thickness Range
CMU. J.Nat.Sci. Special Issue on Nanotechnology (2008) Vol. 7(1) 203 Thickness Dependence of Magnetic Hysteresis of Ising Films in Nano-thickness Range Atchara Punya 1*, Pitak Laoratanakul 2, Rattikorn
More informationarxiv:cond-mat/ v1 [cond-mat.stat-mech] 27 Oct 1997
Non exponential relaxation in fully frustrated models Annalisa Fierro 1, Antonio de Candia 1,2, Antonio Coniglio 1,2 1 Dipartimento di Fisica, Mostra d Oltremare, pad. 19, 80125 Napoli, Italy 2 INFM, Sezione
More informationEvaporation/Condensation of Ising Droplets
, Elmar Bittner and Wolfhard Janke Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, D-04109 Leipzig, Germany E-mail: andreas.nussbaumer@itp.uni-leipzig.de Recently Biskup et
More informationarxiv: v2 [cond-mat.dis-nn] 9 May 2017
Critical behaviour in two-dimensional Coulomb Glass at zero temperature Preeti Bhandari, Vikas Malik, and Syed Rashid Ahmad Department of Physics, Jamia Millia Islamia, New Delhi 1125, India and Department
More informationAbstract In mean-field theory, i.e. infinite-range interactions, the transition between metastable and unstable states of a thermodynamic system is sh
Evidence for sharper than expected transition between metastable and unstable states Dieter W. Heermann and Claudette E. Cordeiro Λ Institut für Theoretische Physik Universität Heidelberg Philosophenweg
More informationDynamics of polar nanodomains and critical behavior of the uniaxial relaxor SBN
Dynamics of polar nanodomains and critical behavior of the uniaxial relaxor SBN W. Kleemann, Th. Braun, Angewandte Physik, Univ. Duisburg, Germany J. Banys, Physics Department, University of Vilnius, Lithuania
More informationHanoi 7/11/2018. Ngo Van Thanh, Institute of Physics, Hanoi, Vietnam.
Hanoi 7/11/2018 Ngo Van Thanh, Institute of Physics, Hanoi, Vietnam. Finite size effects and Reweighting methods 1. Finite size effects 2. Single histogram method 3. Multiple histogram method 4. Wang-Landau
More informationMONTE CARLO METHODS IN SEQUENTIAL AND PARALLEL COMPUTING OF 2D AND 3D ISING MODEL
Journal of Optoelectronics and Advanced Materials Vol. 5, No. 4, December 003, p. 971-976 MONTE CARLO METHODS IN SEQUENTIAL AND PARALLEL COMPUTING OF D AND 3D ISING MODEL M. Diaconu *, R. Puscasu, A. Stancu
More informationInvaded cluster dynamics for frustrated models
PHYSICAL REVIEW E VOLUME 57, NUMBER 1 JANUARY 1998 Invaded cluster dynamics for frustrated models Giancarlo Franzese, 1, * Vittorio Cataudella, 1, * and Antonio Coniglio 1,2, * 1 INFM, Unità di Napoli,
More informationMonte Carlo Study of Planar Rotator Model with Weak Dzyaloshinsky Moriya Interaction
Commun. Theor. Phys. (Beijing, China) 46 (2006) pp. 663 667 c International Academic Publishers Vol. 46, No. 4, October 15, 2006 Monte Carlo Study of Planar Rotator Model with Weak Dzyaloshinsky Moriya
More informationarxiv:cond-mat/ v1 22 Sep 1998
Scaling properties of the cluster distribution of a critical nonequilibrium model Marta Chaves and Maria Augusta Santos Departamento de Física and Centro de Física do Porto, Faculdade de Ciências, Universidade
More informationUniversal scaling behavior of directed percolation and the pair contact process in an external field
Journal of Physics A 35, 005, (00) Universal scaling behavior of directed percolation and the pair contact process in an external field S. Lübeck, and R. D. Willmann,3 Weizmann Institute, Department of
More informationPhase Transitions in Disordered Systems: The Example of the 4D Random Field Ising Model
Phase Transitions in Disordered Systems: The Example of the 4D Random Field Ising Model Nikos Fytas Applied Mathematics Research Centre, Coventry University, United Kingdom Work in collaboration with V.
More informationarxiv:cond-mat/ v1 19 Sep 1995
Large-scale Simulation of the Two-dimensional Kinetic Ising Model arxiv:cond-mat/9509115v1 19 Sep 1995 Andreas Linke, Dieter W. Heermann Institut für theoretische Physik Universität Heidelberg Philosophenweg
More informationSpreadsheet analysis of stability and meta-stability of low-dimensional magnetic. particles using Ising approach accepted version
Spreadsheet analysis of stability and meta-stability of low-dimensional magnetic particles using Ising approach accepted version This is an author-created, un-copyedited version of an article accepted
More informationarxiv:cond-mat/ v4 [cond-mat.dis-nn] 23 May 2001
Phase Diagram of the three-dimensional Gaussian andom Field Ising Model: A Monte Carlo enormalization Group Study arxiv:cond-mat/488v4 [cond-mat.dis-nn] 3 May M. Itakura JS Domestic esearch Fellow, Center
More informationMicroscopic Deterministic Dynamics and Persistence Exponent arxiv:cond-mat/ v1 [cond-mat.stat-mech] 22 Sep 1999
Microscopic Deterministic Dynamics and Persistence Exponent arxiv:cond-mat/9909323v1 [cond-mat.stat-mech] 22 Sep 1999 B. Zheng FB Physik, Universität Halle, 06099 Halle, Germany Abstract Numerically we
More informationOptimization in random field Ising models by quantum annealing
Optimization in random field Ising models by quantum annealing Matti Sarjala, 1 Viljo Petäjä, 1 and Mikko Alava 1 1 Helsinki University of Techn., Lab. of Physics, P.O.Box 1100, 02015 HUT, Finland We investigate
More informationImmigration, integration and ghetto formation
Immigration, integration and ghetto formation arxiv:cond-mat/0209242v1 10 Sep 2002 Hildegard Meyer-Ortmanns School of Engineering and Science International University Bremen P.O.Box 750561 D-28725 Bremen,
More informationThe critical behaviour of the long-range Potts chain from the largest cluster probability distribution
Physica A 314 (2002) 448 453 www.elsevier.com/locate/physa The critical behaviour of the long-range Potts chain from the largest cluster probability distribution Katarina Uzelac a;, Zvonko Glumac b a Institute
More informationIs there a de Almeida-Thouless line in finite-dimensional spin glasses? (and why you should care)
Is there a de Almeida-Thouless line in finite-dimensional spin glasses? (and why you should care) Peter Young Talk at MPIPKS, September 12, 2013 Available on the web at http://physics.ucsc.edu/~peter/talks/mpipks.pdf
More informationRensselaer Polytechnic Institute, 110 8th Street, Troy, NY , USA. Florida State University, Tallahassee, Florida , USA
5 Dynamic Phase Diagram for a Periodically Driven Kinetic Square-lattice Ising Ferromagnet: Finite-size Scaling Evidence for the Absence of a Tri-critical Point G. Korniss 1, P.A. Rikvold 2,3, and M.A.
More informationCRITICAL EXPONENTS OF SMALL ONE-DIMENSIONAL ISING MAGNETIC D. V. Spirin, V. N. Udodov
CRITICAL EXPOETS OF SMALL OE-DIMESIOAL ISIG MAGETIC D. V. Spirin, V.. Udodov Within the framework of a generalied Ising model, a one-dimensional magnetic of a finite length with free ends is considered.
More informationQuantum Annealing in spin glasses and quantum computing Anders W Sandvik, Boston University
PY502, Computational Physics, December 12, 2017 Quantum Annealing in spin glasses and quantum computing Anders W Sandvik, Boston University Advancing Research in Basic Science and Mathematics Example:
More informationAgeing properties of three-dimensional pure and site-diluted Ising ferromagnets
Journal of Physics: Conference Series OPEN ACCESS Ageing properties of three-dimensional pure and site-diluted Ising ferromagnets To cite this article: Vladimir V Prudnikov et al 2014 J. Phys.: Conf. Ser.
More informationarxiv:cond-mat/ v3 [cond-mat.dis-nn] 24 Jan 2006
Optimization in random field Ising models by quantum annealing Matti Sarjala, 1 Viljo Petäjä, 1 and Mikko Alava 1 1 Helsinki University of Techn., Lab. of Physics, P.O.Box 10, 02015 HUT, Finland arxiv:cond-mat/0511515v3
More informationPhase transitions of traffic flow. Abstract
Phase transitions of traffic flow Agustinus Peter Sahanggamu Department of Physics, University of Illinois at Urbana-Champaign (Dated: May 13, 2010) Abstract This essay introduces a basic model for a traffic
More informationMonte Carlo Simulation of the Ising Model. Abstract
Monte Carlo Simulation of the Ising Model Saryu Jindal 1 1 Department of Chemical Engineering and Material Sciences, University of California, Davis, CA 95616 (Dated: June 9, 2007) Abstract This paper
More informationCluster Algorithms to Reduce Critical Slowing Down
Cluster Algorithms to Reduce Critical Slowing Down Monte Carlo simulations close to a phase transition are affected by critical slowing down. In the 2-D Ising system, the correlation length ξ becomes very
More informationA New Method to Determine First-Order Transition Points from Finite-Size Data
A New Method to Determine First-Order Transition Points from Finite-Size Data Christian Borgs and Wolfhard Janke Institut für Theoretische Physik Freie Universität Berlin Arnimallee 14, 1000 Berlin 33,
More informationCritical Dynamics of Two-Replica Cluster Algorithms
University of Massachusetts Amherst From the SelectedWorks of Jonathan Machta 2001 Critical Dynamics of Two-Replica Cluster Algorithms X. N. Li Jonathan Machta, University of Massachusetts Amherst Available
More informationPhenomenology and Models of Exchange Bias in Core /Shell Nanoparticles
Phenomenology and Models of Exchange Bias in Core /Shell Nanoparticles Xavier Batlle and Amílcar Labarta Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia Universitat de Barcelona,
More informationInterface depinning in a disordered medium - numerical results
Interface depinning in a disordered medium - numerical results Heiko Leschhorn Theoretische Physik III, Ruhr-Universität Bochum, Postfach 102148, D-4630 Bochum, Germany arxiv:cond-mat/9302039v1 26 Feb
More informationQuantum annealing by ferromagnetic interaction with the mean-field scheme
Quantum annealing by ferromagnetic interaction with the mean-field scheme Sei Suzuki and Hidetoshi Nishimori Department of Physics, Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan
More informationSolving the Schrödinger equation for the Sherrington Kirkpatrick model in a transverse field
J. Phys. A: Math. Gen. 30 (1997) L41 L47. Printed in the UK PII: S0305-4470(97)79383-1 LETTER TO THE EDITOR Solving the Schrödinger equation for the Sherrington Kirkpatrick model in a transverse field
More informationLogarithmic corrections to gap scaling in random-bond Ising strips
J. Phys. A: Math. Gen. 30 (1997) L443 L447. Printed in the UK PII: S0305-4470(97)83212-X LETTER TO THE EDITOR Logarithmic corrections to gap scaling in random-bond Ising strips SLAdeQueiroz Instituto de
More informationarxiv:cond-mat/ v1 18 Mar 2003
Hysteresis loop of a nanoscopic magnetic array A. Kaczanowski, K. Malarz and K. Ku lakowski arxiv:cond-mat/3333v1 18 Mar 23 Department of Applied Computer Science, Faculty of Physics and Nuclear Techniques,
More informationv n,t n
THE DYNAMICAL STRUCTURE FACTOR AND CRITICAL BEHAVIOR OF A TRAFFIC FLOW MODEL 61 L. ROTERS, S. L UBECK, and K. D. USADEL Theoretische Physik, Gerhard-Mercator-Universitat, 4748 Duisburg, Deutschland, E-mail:
More informationMetropolis Monte Carlo simulation of the Ising Model
Metropolis Monte Carlo simulation of the Ising Model Krishna Shrinivas (CH10B026) Swaroop Ramaswamy (CH10B068) May 10, 2013 Modelling and Simulation of Particulate Processes (CH5012) Introduction The Ising
More informationVSOP19, Quy Nhon 3-18/08/2013. Ngo Van Thanh, Institute of Physics, Hanoi, Vietnam.
VSOP19, Quy Nhon 3-18/08/2013 Ngo Van Thanh, Institute of Physics, Hanoi, Vietnam. Part III. Finite size effects and Reweighting methods III.1. Finite size effects III.2. Single histogram method III.3.
More informationQuantum and classical annealing in spin glasses and quantum computing. Anders W Sandvik, Boston University
NATIONAL TAIWAN UNIVERSITY, COLLOQUIUM, MARCH 10, 2015 Quantum and classical annealing in spin glasses and quantum computing Anders W Sandvik, Boston University Cheng-Wei Liu (BU) Anatoli Polkovnikov (BU)
More informationStatistical description of magnetic domains in the Ising model
arxiv:0804.3522v1 [cond-mat.stat-mech] 22 Apr 2008 Statistical description of magnetic domains in the Ising model K. Lukierska-Walasek Institute of Physics University of Zielona Góra ul. Z. Szafrana 4a,
More informationarxiv:cond-mat/ v2 [cond-mat.dis-nn] 11 Nov 2009
arxiv:cond-mat/0611568v2 [cond-mat.dis-nn] 11 Nov 2009 On the universality class of the 3d Ising model with long-range-correlated disorder D. Ivaneyko a,, B. Berche b, Yu. Holovatch c,d, J. Ilnytskyi c,e
More informationICCP Project 2 - Advanced Monte Carlo Methods Choose one of the three options below
ICCP Project 2 - Advanced Monte Carlo Methods Choose one of the three options below Introduction In statistical physics Monte Carlo methods are considered to have started in the Manhattan project (1940
More informationIs the Sherrington-Kirkpatrick Model relevant for real spin glasses?
Is the Sherrington-Kirkpatrick Model relevant for real spin glasses? A. P. Young Department of Physics, University of California, Santa Cruz, California 95064 E-mail: peter@physics.ucsc.edu Abstract. I
More informationList of published papers
List of published papers Zsolt Gulácsi 1. Zs. Gulácsi,M.Popescu, I.Rus: ThemagneticPropertiesoftheHo 2 Fe 12 x Al x compounds, Studia Univ. Babes Bolyai Cluj, 23, 63 (1978). 2. M. Crisan, Zs. Gulácsi:
More information8.3.2 The finite size scaling method
232 Chapter 8: Analysing Monte Carlo data In general we don t know this value, which makes it difficult to perform the fit. It is possible to guess T c and then vary the guess to make the line in Figure
More informationProgress toward a Monte Carlo Simulation of the Ice VI-VII Phase Transition
Progress toward a Monte Carlo Simulation of the Ice VI-VII Phase Transition Christina Gower 2010 NSF/REU PROJECT Physics Department University of Notre Dame Advisor: Dr. Kathie E. Newman August 6, 2010
More informationPersistence in Random Bond Ising Models of a Socio-Econo Dynamics in High Dimensions. Abstract
Persistence in Random Bond Ising Models of a Socio-Econo Dynamics in High Dimensions S. Jain arxiv:physics/0610160v1 [physics.soc-ph] 20 Oct 2006 Information Engineering, The Neural Computing Research
More informationThe Magnetic Properties of Superparamagnetic Particles by a Monte Carlo Method
The Magnetic Properties of Superparamagnetic Particles by a Monte Carlo Method D. A. Dimitrov and G. M. Wysin Department of Physics Kansas State University Manhattan, KS 6656-261 (June 19, 1996) We develop
More informationMonte Carlo study of the Baxter-Wu model
Monte Carlo study of the Baxter-Wu model Nir Schreiber and Dr. Joan Adler Monte Carlo study of the Baxter-Wu model p.1/40 Outline Theory of phase transitions, Monte Carlo simulations and finite size scaling
More informationarxiv: v1 [cond-mat.str-el] 28 Oct 2015
Spin- J J J ferromagnetic Heisenberg model with an easy-plane crystal field on the cubic lattice: A bosonic approach D. C. Carvalho, A. S. T. Pires, L. A. S. Mól Departamento de ísica, Instituto de Ciências
More informationBranislav K. Nikolić
Interdisciplinary Topics in Complex Systems: Cellular Automata, Self-Organized Criticality, Neural Networks and Spin Glasses Branislav K. Nikolić Department of Physics and Astronomy, University of Delaware,
More informationCritical behavior of nonequilibrium phase transitions to magnetically ordered states
PHYSICAL REVIEW E, VOLUME 65, 4611 Critical behavior of nonequilibrium phase transitions to magnetically ordered states Thomas Birner, Karen Lippert, Reinhard Müller, Adolf Kühnel, and Ulrich Behn Institut
More informationPhase Transitions of Random Binary Magnetic Square Lattice Ising Systems
I. Q. Sikakana Department of Physics and Non-Destructive Testing, Vaal University of Technology, Vanderbijlpark, 1900, South Africa e-mail: ike@vut.ac.za Abstract Binary magnetic square lattice Ising system
More informationPBS: FROM SOLIDS TO CLUSTERS
PBS: FROM SOLIDS TO CLUSTERS E. HOFFMANN AND P. ENTEL Theoretische Tieftemperaturphysik Gerhard-Mercator-Universität Duisburg, Lotharstraße 1 47048 Duisburg, Germany Semiconducting nanocrystallites like
More informationPHYSICAL REVIEW LETTERS
PHYSICAL REVIEW LETTERS VOLUME 76 4 MARCH 1996 NUMBER 10 Finite-Size Scaling and Universality above the Upper Critical Dimensionality Erik Luijten* and Henk W. J. Blöte Faculty of Applied Physics, Delft
More informationThe Monte Carlo Method in Condensed Matter Physics
The Monte Carlo Method in Condensed Matter Physics Edited by K. Binder With Contributions by A. Baumgärtner K. Binder A.N. Burkitt D.M. Ceperley H. De Raedt A.M. Ferrenberg D.W. Heermann H.J. Herrmann
More informationMagnetic Properties and Scaling Behavior in Perovskite like La 0.7 (Ba 1-x Pb x ) 0.3 CoO 3 System
Mat. Res. Soc. Symp. Proc. Vol. 674 21 Materials Research Society Magnetic Properties and Scaling Behavior in Perovskite like La.7 (Ba 1-x Pb x ).3 CoO 3 System Chiung-Hsiung Chen, Ting-Sheng Huang and
More informationarxiv: v1 [cond-mat.dis-nn] 12 Nov 2014
Representation for the Pyrochlore Lattice arxiv:1411.3050v1 [cond-mat.dis-nn] 12 Nov 2014 André Luis Passos a, Douglas F. de Albuquerque b, João Batista Santos Filho c Abstract a DFI, CCET, Universidade
More informationSUPPLEMENTARY INFORMATION
Materials and Methods Single crystals of Pr 2 Ir 2 O 7 were grown by a flux method [S1]. Energy dispersive x-ray analysis found no impurity phases, no inhomogeneities and a ratio between Pr and Ir of 1:1.03(3).
More informationCONTINUOUS- AND FIRST-ORDER PHASE TRANSITIONS IN ISING ANTIFERROMAGNETS WITH NEXT-NEAREST- NEIGHBOUR INTERACTIONS
Continuous- Rev.Adv.Mater.Sci. and first-order 14(2007) phase 1-10 transitions in ising antiferromagnets with next-nearest-... 1 CONTINUOUS- AND FIRST-ORDER PHASE TRANSITIONS IN ISING ANTIFERROMAGNETS
More informationBond Dilution Effects on Bethe Lattice the Spin-1 Blume Capel Model
Commun. Theor. Phys. 68 (2017) 361 365 Vol. 68, No. 3, September 1, 2017 Bond Dilution Effects on Bethe Lattice the Spin-1 Blume Capel Model Erhan Albayrak Erciyes University, Department of Physics, 38039,
More informationPLEASE SCROLL DOWN FOR ARTICLE
This article was downloaded by: [Uniwersytet Slaski] On: 14 October 2008 Access details: Access Details: [subscription number 903467288] Publisher Taylor & Francis Informa Ltd Registered in England and
More informationConcentration of magnetic transitions in dilute magnetic materials
Journal of Physics: Conference Series OPEN ACCESS Concentration of magnetic transitions in dilute magnetic materials To cite this article: V I Beloon et al 04 J. Phys.: Conf. Ser. 490 065 Recent citations
More informationThe relaxation to equilibrium in one-dimensional Potts models
.I. Indian Inst. Sci., May June 1995, 75, 297-304 Indian Institute of Science The relaxation to equilibrium in one-dimensional Potts models DEEPAK DHAR Theoretical Physics Group, Tata Institute of Fundamental
More informationKeywords: frustration, spin orders, magnetization plateau, triangular antiferromagnets PACS numbers: Hk, Ej, Ln
Revised manuscript submitted to Journal of Physics: Condensed Matter (JPCM-0656) Effect of further-neighbor interactions on the magnetization behaviors of the Ising model on a triangular lattice J. Chen,
More informationPhase Transitions in Spin Glasses
Phase Transitions in Spin Glasses Peter Young Talk available at http://physics.ucsc.edu/ peter/talks/sinica.pdf e-mail:peter@physics.ucsc.edu Supported by the Hierarchical Systems Research Foundation.
More informationarxiv: v1 [cond-mat.dis-nn] 13 Jul 2015
Spin glass behavior of the antiferromagnetic Heisenberg model on scale free network arxiv:1507.03305v1 [cond-mat.dis-nn] 13 Jul 2015 Tasrief Surungan 1,3, Freddy P. Zen 2,3, and Anthony G. Williams 4 1
More informationGiant Enhancement of Quantum Decoherence by Frustrated Environments
ISSN 0021-3640, JETP Letters, 2006, Vol. 84, No. 2, pp. 99 103. Pleiades Publishing, Inc., 2006.. Giant Enhancement of Quantum Decoherence by Frustrated Environments S. Yuan a, M. I. Katsnelson b, and
More informationarxiv: v1 [cond-mat.stat-mech] 22 Sep 2009
Phase diagram and critical behavior of the square-lattice Ising model with competing nearest- and next-nearest-neighbor interactions Junqi Yin and D. P. Landau Center for Simulational Physics, University
More informationarxiv:cond-mat/ Jul 1996
QUANTUM SPIN GLASSES Heiko Rieger 1 and A. Peter Young 2 1 HLRZ c/o Forschungszentrum Jülich, 52425 Jülich, Germany 2 Department of Physics, University of California, Santa Cruz, CA 95064, USA arxiv:cond-mat/9607005
More informationTopological defects and its role in the phase transition of a dense defect system
Topological defects and its role in the phase transition of a dense defect system Suman Sinha * and Soumen Kumar Roy Depatrment of Physics, Jadavpur University Kolkata- 70003, India Abstract Monte Carlo
More information4. Cluster update algorithms
4. Cluster update algorithms Cluster update algorithms are the most succesful global update methods in use. These methods update the variables globally, in one step, whereas the standard local methods
More informationScaling Theory. Roger Herrigel Advisor: Helmut Katzgraber
Scaling Theory Roger Herrigel Advisor: Helmut Katzgraber 7.4.2007 Outline The scaling hypothesis Critical exponents The scaling hypothesis Derivation of the scaling relations Heuristic explanation Kadanoff
More informationQuantum annealing for problems with ground-state degeneracy
Proceedings of the International Workshop on Statistical-Mechanical Informatics September 14 17, 2008, Sendai, Japan Quantum annealing for problems with ground-state degeneracy Yoshiki Matsuda 1, Hidetoshi
More informationStudy of the Magnetic Properties of a Lieb Core-Shell Nano-Structure: Monte Carlo Simulations
Study of the Magnetic Properties of a Lieb Core-Shell Nano-Structure: Monte Carlo Simulations S. Aouini, S. Ziti, H. Labrim,* and L. Bahmad,* Laboratoire de la Matière Condensée et Sciences Interdisciplinaires
More informationUniversality class of triad dynamics on a triangular lattice
Universality class of triad dynamics on a triangular lattice Filippo Radicchi,* Daniele Vilone, and Hildegard Meyer-Ortmanns School of Engineering and Science, International University Bremen, P. O. Box
More informationMean-Field Analysis of the Ising Hysteresis Relaxation Time
Chiang Mai J. Sci. 2009; 36(3) 263 Chiang Mai J. Sci. 2009; 36(3) : 263-275 www.science.cmu.ac.th/journal-science/josci.html Contributed Paper Mean-Field Analysis of the Ising Hysteresis Relaxation Time
More informationarxiv:cond-mat/ v1 [cond-mat.other] 4 Aug 2004
Conservation laws for the voter model in complex networks arxiv:cond-mat/0408101v1 [cond-mat.other] 4 Aug 2004 Krzysztof Suchecki, 1,2 Víctor M. Eguíluz, 1 and Maxi San Miguel 1 1 Instituto Mediterráneo
More informationMonte Carlo Simulations in Statistical Physics
Part II Monte Carlo Simulations in Statistical Physics By D.Stauffer Introduction In Statistical Physics one mostly deals with thermal motion of a system of particles at nonzero temperatures. For example,
More information