SDr 33 r ceE~a Springer Proceedings in Physics Managing Editor: H. K. V. Lotsch Volume 30 Short-Wavelength Lasers and Their Applications Editor: C. Yamanaka Volume 31 Quantum String Theory Editors: N. Kawamoto and T. Kugo Volume 32 Universalities in Condensed Matter Editors: R. Jullien, L. Peliti, R. Rammal, and N. Boccara Volume 33 Computer Simulation Studies in Condensed Matter Physics: Recent Developments Editors: D. P. Landau, K. K. Mon, and H.-B. Schuttler Volumes 1 - 29 are listed on the back inside cover Computer Simulation Studies in Condensed Matter Physics Recent Developments Proceedings of the Workshop, Athens, GA, USA, February 15-26, 1988 Editors: D. P. Landau, K. K. Mon, and H.-B. Schuttler With 101 Figures Springer-Verlag Berlin Heidelberg New York London Paris Tokyo Professor David P. Landau, Ph. D. Professor K. K. Mon, Ph. D. Professor Heinz-Bernd Schuttler, Ph. D. Center for Simulational Physics, The University of Georgia, Athens, GA 30602, USA ISBN-13: 978-3-642-93402-5 e-ISBN-13: 978-3-642-93400-1 001: 10.1007/978-3-642-93400-1 Library of Congress Cataloging-in-Publication Data. Computer simulation studies in condensed matter physics: recent developments: proceedings of the workshop. Athens, GA, USA, February 15-26, 1988/ editors, D. P. Landau, K. K. Mon, and H.-B. Schuttler. (Springer proceedings in physics; v. 33) Includes index. (U.S.: alk. paper) 1. Condensed matter - Computer simulation - Congresses. I. Landau, David P. II. Mon, K. K. (Kin K.), 1950-. III. Schuttler, Heinz-Bernd, 1956-. IV. Series. QC173.4.C65C65 1988 530.4'1-dc 19 88-30707 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in other ways, and storage in data banks. Duplication of this publication or parts thereof is only permitted under the provisions ofthe German Copyright Lawof September 9,1965, in its version of June 24, 1985, and a copyright fee must always be paid. Violations fall under the prosecution act of the German Copyright Law. © Springer-Verlag Berlin Heidelberg 1988 Softcover reprint of the hardcover 1s t edition 1988 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exemptfrom the relevant protective laws and regulations and there fore free for general use. 2154/3150-543210 - Printed on acid-free paper Preface Computer simulation studies in condensed matter physics represent a rapidly changing field, making significant contributions in techniques and in new results to important physical problems. The workshop on "Recent Developments in Com puter Simulation Studies in Condensed Matter Physics", held at the Center for Simulational Physics at the University of Georgia, February 14-26, 1988, was an attempt to bring together some of the practitioners in this field and to provide a forum for the presentation and exchange of new ideas and recent developments. These proceedings are a record of the workshop and are published with the goal of timely dissemination of the papers to a wider audience. Although by their very nature workshops are limited in their scope of coverage, a broad range of current topics is discussed. The papers present new techniques and results on both static and dynamical phenomena of classical and quantum mechanical systems. The reader will find descriptions of studies of static properties as well as time-dependent ones where time may be real time, stochastic time or imaginary (path integral) time. A substantial portion of the material, the first part of the proceedings, deals with simulations of classical systems. Monte Carlo simulations are presented for simple Ising models. On the one hand, the reader will find here new approaches suggested for avoiding critical slowing down, and on the other, there are descriptions of the study of critical slowing down using standard techniques. Both standard and novel Monte Carlo methods have been used to study static properties at phase transitions. New results for classical spin dynamics are discussed. New material is presented for the formation of aggregates. Molecular dynamics and/or Monte Carlo approaches have been developed for studying fluid flow as well as for polymer systems, adsorbed monolayers and crystal growth. The second part of the proceedings is devoted to the simulation of quantum systems. New results for interacting boson and fermion systems, adsorbed 4He monolayers and the electronic structure of clusters have been obtained by numer ical functional and path integral techniques. Novel variational wave functions and minimization techniques are discussed in the context of solid 4He, and the electronic structure of real atoms and solids. Promising new hybrid methods have been developed by combining more conventional quantum methods, such as quantum Monte Carlo or density functional theory, with well-established classi cal techniques, such as molecular dynamics. The workshop also included several presentations about emerging computer technologies and programming methods. but for the most part no written record is available. v We hope that the readers will benefit from papers in their own special field as well as gain new ideas from other related specialties. This workshop was made possible through the generous support of the Ad vanced Computational Methods Center, the Department of Physics and Astronomy, and the Vice President for Research at the University of Georgia. Athens, GA, USA D.P. Landau April 1988 KK Man H.-B. Schuttler VI Contents Introduction By D.P. Landau, K.K. Mon, and H.-B. Schuttler 1 Part I Classical Systems New Numerical Algorithms for Critical Phenomena (Multi-Grid Methods and All That) By A.D. Sokal ........................................ 6 Multigrid Monte Carlo Methods By E. Loh, Jr. (With 1 Figure) ................. . . . . . . . . . . . . 19 Monte Carlo Simulations Using the Gaussian Ensemble By M.S.S. Challa and J.H. Hetherington (With 7 Figures) . . . . . . . . . . . 31 Classical Spin Dynamics in the Two-Dimensional Anisotropic Heisenberg Model By G.M. Wysin, M.E. Gouvea, A.R. Bishop, and F.G. Mertens (With 6 Figures) .............................. . . . . . . . . . 40 Simulation Study of Light Scattering from Soot Agglomerates By R.D. Mountain (With 4 Figures) ......................... 49 Simulation of Non-equilibrium Growth and Aggregation Processes By P. Meakin (With 9 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Growth by Gradients: Fractal Growth and Pattern Formation in a Laplacian Field By F. Family (With 6 Figures) ............................. 65 Dynamics of Dense Polymers: A Molecular Dynamics Approach By G.S. Grest and K. Kremer (With 5 Figures) ...... . . . . . . . . . . . . 76 Monte Carlo Simulations of Polymer Systems By K. Binder (With 9 Figures) ............................. 84 Molecular Dynamics: A New Approach to Hydrodynamics? By D.C. Rapaport (With 5 Figures) .......................... 98 Molecular Dynamics Simulations in Material Science and Condensed Matter Physics By U. Landman (With 8 Figures) ........................... 108 VII Simulations of Oxygen Monolayer and Bilayer Systems By K.M. Flurchick and R.D. Etters (With 3 Figures) .............. 124 Part II Quantum Systems Classical and Quantum Simulations of Quasi Two-Dimensional Condensed Phases: Krypton and Helium on Graphite By F.F. Abraham (With 7 Figures) .......................... 134 Path-Integral and Real-Time Dynamics Simulations of Quantum Systems By U. Landman (With 5 Figures) ........................... 144 Superfluidity of a Two-Dimensional Bose-Coulomb Gas By D. Peters and B. Alder (With 3 Figures) .................... 157 Quantum Monte Carlo Studies of the Holstein Model By R.T. Scalettar, N.E. Bickers, and D.J. Scalapino (With 2 Figures) 166 Structure of the Wave Function of Crystalline 4He By S.A. Vitiello, KJ. Runge, and M.H. Kalos (With 3 Figures) . . . . . .. 172 Electronic Structure Calculation by Nonlinear Optimization: Application to Metals By R. Benedek, B.I. Min, C. Woodward, and J. Garner (With 2 Figures) 179 A Method for Determining Many Body Wavefunctions By C.J. Umrigar, K.G. Wilson, and J.W. Wilkins (With 1 Figure) 185 Part III Computer Graphics Computer Graphics for Scientists and Engineers By S. Follin (With 4 Figures) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 196 Part IV Contributed Papers Monte Carlo Calculation of Transfer Matrix Eigenvalues By M.P. Nightingale and R.G. Caflisch ....................... 208 Finite Size Effects at First-Order Phase Transitions Revisited By P. Peczak and D.P. Landau (With 1 Figure) ................ " 214 Correlation Time Measurements for the d=2 Ising Model By A.M. Ferrenberg and R.H. Swendsen (With 2 Figures) .......... 217 Monte Carlo Study of the Critical Dynamics at the Surface of an Ising Model By P.A. Slotte, S. Wansleben, and D.P. Landau (With 1 Figure) ...... 222 A New Model of Interactive Percolation By S.R. Anderson and F. Family (With 4 Figures) . . . . . . . . . . . . . . .. 225 VIII MD Simulation of 2D Rb Liquid and Solid Phases in Graphite By J.D. Fan, O.A. Karim, G. Reiter, and S.C. Moss (With 3 Figures) 229 Index of Contributors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 233 IX Introduction D.P. Landau, K.K. Mon, and H.-B. Schuttler Center for Simulational Physics, University of Georgia, Athens, GA 30602, USA Computer simulations have become recognized as a new approach to research in physics; they provide great flexibility in the choice of parameters to be included, the ensemble to be used, and even the questions to be answered. Simulations provide not only numerical data but also allow the visualization of microscopic behavior (through graphics output) which helps flesh out our intuitive understanding of the processes at work. Early work was done using computers which were considerably slower than today's personal computers, and it was only in the late 1960's that computer speed had increased to the point that detailed studies of physical problems became possible. A broad range of problems which have already been attacked using Monte Carlo methods has been summarized in two earlier volumes in the Springer-Verlag series on Topics in Current Physics and we refer the newcomer to the field to these books [1, 2]. The proceedings of this workshop concentrate instead on the most recent developments in the field of computer simulations in condensed matter physics. Monte Carlo methods determine the properties of interacting many-particle systems by generating (carefully chosen) sample configurations of the system and using these states to estimate the actual distribution of the total number of states. New configurations are generated from precedinp; ones using "single site" changes, but "multi-spin" methods may speed up the computation substantially either through the implementation of vector operations or through modification of the fundamental dynamic time scale. Increasing accuracy is of course obtainable by simply using larger systems and generating more states. A "standard" unit for measuring the lengths of Monte Carlo runs is the MCS/site or Monte Carlo Step per site, which represents one examination of every site in the system. Whereas two decades ago only a few hundred MCS/site were generally possible for classical systems, today run lengths for simple models may he measured in millions of MCS/site. The speed of modern computers has also made it possible to examine more realistic models, which of course consume far more computer time than do simple theoretical systems. In these proceedings you will find data obtained using both Cyber 205 and CRA Y /XMP supercomputers; on the other hand there are also very high resolution data for simple, small systems which have been produced by using a totally dedicated micro-Vax. Whereas Monte Carlo methods may be applied directly to collections of classical particles, they may be used only indirectly for the exploration of quantum systems. Quantum behavior can be produced only with the inclusion of an extra degree of freedom (or added dimension) before simulations are introduced and the second part of these proceedings presents some novel ways in which this may be done. A second simulation approach, Molecular Dynamics, involves the integration of coupled equations of motion which govern the time development of classical systems. The resultant (true) dynamics is different than the (stochastic) kinetic behaviot resulting from Monte Carlo simulations although it is presently possible to extend such studies to only very short periods of physical time.In these proceedings the reader will find descriptions of the application of molecular dynamics techniques to larger and to more complex collections of interacting particles than is usually found in the literature. The representaion of simulations data through computer graphics is gaining in importance and the state of the art in computer graphics is discussed in these proceedings by Follin. Springer Proceedings in Physics Vol. 33: Computer Simulation Studies in Condensed Matter Physics Editors: D. P. Landau· K. K. Mon· H-B. Schiittler © Springer-Verlag Berlin Heidelberg 1988