MOMENTUM DISTRIBUTIONS MOMENTUM DISTRIBUTIONS Edited by Richard N. Silver Los Alamos National Laboratory Los Alamos, New Mexico and Paul E. Sokol The Pennsylvania State University University Park, Pennsylvania Springer Science+Business Media, LLC Library of Congress Cataloging in Publication Data Momentum distributions / edited by Richard N. Silver and Paul E. Sokol. p. cm. Proceedings of the workshop on Momentum Distributions, held October 24-26, 1988, at Argonne National Laboratory. Includes bibliographical references. ISBN 978-1-4899-2556-5 1. Momentum distributions—Congresses. 2. Neutrons—Scattering—Congresses. 3. Quantum liquids—Congresses. I. Silver, Richard N. II. Sokol, Paul E. III. Workshop on Momentum Distributions (1988: Argonne National Laboratory) QC173.4.M67M66 1989 89-22841 530-dc20 CIP ISBN 978-1-4899-2556-5 ISBN 978-1-4899-2554-1 (eBook) DOI 10.1007/978-1-4899-2554-1 Proceedings of a workshop on Momentum Distributions, held October 24-26, 1988, at Argonne National Laboratory, Argonne, Illinois © 1989 Springer Science+Business Media New York Originally published by Plenum Press, New York in 1989 Softcover reprint of the hardcover 1st edition 1989 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE This volume presents the proceedings of the Workshop on Momentum Distributions held on October 24 to 26, 1988 at Argonne National Laboratory. This workshop was motivated by the enormous progress within the past few years in both experimental and theoretical studies of momentum distributions, by the growing recognition of the importance of momentum distributions to the characterization of quantum many-body systems, and especially by the realization that momentum distribution studies have much in common across the entire range of modern physics. Accordingly, the workshop was unique in that it brought together researchers in nuclear physics, electronic systems, quantum fluids and solids, and particle physics to address the common elements of momentum distribution studies. The topics dis cussed in the workshop spanned more than ten orders of magnitude range in charac teristic energy scales. The workshop included an extraordinary variety of interactions from Coulombic to hard core repulsive, from non-relativistic to extreme relativistic. Nevertheless, the discussions were united around common themes which include the methods to perform ab initio calculations of momentum distributions, the impulse approximation used to extract momentum distributions from scattering experiments at high energy and momentum transfers, the corrections to the impulse approximation such as due to final state interactions and the excitation of internal degrees of free dom, and the interpretation of momentum distribution data in terms of what they reveal about the underlying wave functions and interaction potentials in strongly corre lated many-body systems. Judged by the spirited exchanges among scientists from diverse areas of physics which took place at the meeting, and by the efforts which the contributors to this volume have made to make their papers intelligible for non-spe cialists, we believe the conference was very successful in meeting its objectives. These were to survey the state-of-the-art in momentum distribution studies and to provide cross-disciplinary fertilization. This volume begins with an introduction to momentum distributions in the over view paper by P. E. Sokol, R. N. Silver, and J. W. Clark. The intent is to establish a common language, to identify unifying themes and to compare momentum distribution studies in various subfields of physics. We hope the overview will help the reader to appreciate the more specialized articles which follow in these proceedings. The work shop consisted of a set of invited talks, which are organized in this volume in the same order as they were presented at the meeting, while contributed papers were presented in a poster session. The workshop summary by R. O. Simmons at the end of the proceedings is intended to provide readers with one expert's view of the significant v new developments in momentum distribution studies as revealed by the workshop. Other events at the workshop, which regretably we are not able to include in these proceedings, included a lively discussion session chaired by J. W. Clark, an entertain ing history of the "Quest for nCp)" presented by E. C. Svensson, and invited talks presented by S. E. Koonin and J. H. Hetherington. We wish to thank the staff of Argonne National Laboratory who helped to organ ize and support this Workshop. Financial support was graciously provided by the Intense Pulsed Neutron Source through its Director, Bruce Brown, by the Division of Educational Programs, through Harold Myron, and by the University of Chicago, through Joel Snow. We thank Mariam Holden and the conference support staff at Argonne for their able assistance in logistical arrangements for the meeting. We thank Plenum Publishing Corporation, and especially Melanie Yelity, for their expert work in producing these proceedings. We gratefully acknowledge the advice of J. W. Clark regarding the selection of invited papers. We also thank the able chairpersons of the sessions: P. A. Whitlock, A. S. Rinat, W. Stirling, R. B. Wiringa, A. Griffin, S. K. Sinha, and J. M. Carpenter. Finally, we would also acknowledge our individual research grants. RNS is sup ported by the OBESIDMS funding of the Los Alamos Neutron Scattering Center at Los Alamos National Laboratory. PES is supported by NSF grant DMR-8704288 and OBESIDMS support of the Intense Pulsed Neutron Source at Argonne National Labo ratory under DOE grant W-31-109-ENG-38. Los Alamos, New Mexico Richard N. Silver University Park, Pennsylvania Paul E. Sokol vi CONTENTS Momentum Distributions: An Overview 1 P. E. Sokol *, R. N. Silver, J. W. Clark MOMENTUM DISTRIBUTION 1HEORY Overview of Momentum Distribution Calculations 39 J. W. Clark *, M. L. Ristig Momentum Distributions in Quantum Liquids from Green's Function Monte Carlo Calculations 59 R. M. Panoff *, P. A. Whitlock The Momentum Distribution of 4He at Non-zero Temperature 71 D. M. Ceperley * Momentum Distributions in Liquid 4He at Low Temperatures: Variational Methods 81 E. Manousakis * IMPULSE APPROXIMATION AND CORRECTIONS X and Y Scaling 95 G. B. West * Final State Effects in Quantum Fluids 111 R. N. Silver * Approach to the Impulse Approximation in Quantum Solids and Fluids 123 H. R. Glyde *, W. G. Stirling * Denotes Speaker vii QUANTUM FLUIDS AND SOLIDS Momentum Distributions in Liquid Helium 139 P. E. Sokol ., T. R. So snick, W. M. Snow Neutron Scattering Studies of n(p) at Reactor Sources 159 H. A. Mook * NUCLEAR PHYSICS Momentum Distributions from Quasielastic Electron-Nucleus Scattering 175 I. Sick * What Would We Like to Know About n(p) in Nuclear Physics? 187 O. Benhar, A. Fabrocini, S. Fantoni • HYDRO GENIC SYSTEMS Hydrogen and Hydrogen Impurities in Rare Gases 203 K. W. Herwig ., R. O. Simmons Hydrogen Potential in f3-V2H Studied by Deep Inelastic Neutron Scattering 213 R. Hempelmann *, D. L. Price, G. Reiter, D. Richter Theory of Momentum Distributions and their Measurement for Hydrogen in Solids 221 G. F. Reiter * ELECTRONIC SYSTEMS Momentum Distributions in Strongly Correlated Electron Systems: Heavy Fermions, Mott Insulators and High Temperature Superconductors 235 S. Doniach * X-Ray Compton Scattering from Condensed Matter Systems 249 P. M. Platzman • Measuring the Momentum Distribution of the Unpaired Spin Electrons in Ferromagnets using Synchrotron Radiation 261 D. M. Mills • Positron and Positronium Momentum Spectroscopy in Solids: An Overview 273 S. Berko • Fermi Surfaces by Positron Annihilation in YBa2Cu30x 287 L. C. Smedskjaer • viii EXPERIMENTAL TECHNIQUES FOR MOMENTUM DISTRIBUTIONS Neutron Experimental Techniques for n(p) 295 R. Holt .. , J. Mayers, A. Taylor The Determination of Electron Momentum Density Distributions 307 M. J. Cooper .. Experimental Determination of Momentum Distributions in Nuclear Physics 319 D. Day" CONTRIBUTED PAPERS Resolution in Deep Inelastic Neutron Scattering using Pulsed Neutron Sources 333 C. Andreani, G. Baciocco, R. Holt, J. Mayers Contribution of Meson Exchange Currents to the Nuclear Quasielastic Peak 341 P. G. Blunden, M. N. Butler Single-Particle Strength and Nuclear Response Functions 345 W. H. Dickoff, M. G. E. Brand, K. Allart, A. Ramos, A. Polls High Energy Inelastic Neutron Scattering from Hydrogen in Cesium Intercalated Graphite 351 G. J. Kellogg, P. E. Sokol, J. White Initial State Effects in Deep Inelastic Neutron Scattering 355 J. Mayers, C. Andreani, G. Baciocco On the Approach to the Scaling Limit of the Response of Quantum Gases 361 A. S. Rinat Generalized Momentum Distributions 365 M. L. Ristig, J. W. Clark Final-State Effects in Deep-Inelastic Neutron Scattering 371 V. F. Sears Determination of Momentum Distributions from Deep Inelastic Neutron Scattering Experiments - a Bayesian Study 377 D. S. Sivia, R. N. Silver Time Evolution of the Momentum Distribution of a Bose Gas Near Condensation 381 D. W. Snoke, J. P. Wolfe Final State Effects in Liquid 4He: An Experimental Test 385 P. E. Sokol, R. N. Silver, T. R. Sosnick, W. M. Snow ix Momentum Distributions of Liquid 4He in Aerogel Glass 393 W. M. Snow, P. E. Sokol WRAP-UP Summary: Workshop on Momentum Distributions 401 R. O. Simmons * Participants 409 Index 411 x