THE FRONTIERS COLLECTION Giovanni Battimelli Giovanni Ciccotti Pietro Greco COM PU T ER MEETS THEORETICAL PHYSICS The New Frontier of Molecular Simulation THE FRONTIERS COLLECTION Series Editors Avshalom C. Elitzur, Iyar, Israel Institute of Advanced Research, Rehovot, Israel Zeeya Merali, Foundational Questions Institute, Decatur, GA, USA Thanu Padmanabhan, Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, India Maximilian Schlosshauer, Department of Physics, University of Portland, Portland, OR, USA Mark P. Silverman, Department of Physics, Trinity College, Hartford, CT, USA Jack A. Tuszynski, Department of Physics, University of Alberta, Edmonton, AB, Canada Rüdiger Vaas, Redaktion Astronomie, Physik, bild der wissenschaft, Leinfelden-Echterdingen, Germany The books in this collection are devoted to challenging and open problems at the forefront of modern science and scholarship, including related philosophical debates. In contrast to typical research monographs, however, they strive to present their topics in a manner accessible also to scientifically literate non-specialists wishing to gain insight into the deeper implications and fascinating questions involved. Taken as a whole, the series reflects the need for a fundamental and interdisciplinary approach to modern science and research. Furthermore, it is intended to encourage active academics in all fields to ponder over important and perhaps controversial issues beyond their own speciality. Extending from quantum physics and relativity to entropy, consciousness, language and complex systems—the Frontiers Collection will inspire readers to push back the frontiers of their own knowledge. More information about this series at http://www.springer.com/series/5342 Giovanni Battimelli • Giovanni Ciccotti • Pietro Greco Computer Meets Theoretical Physics The New Frontier of Molecular Simulation 123 Giovanni Battimelli Giovanni Ciccotti Department of Physics Department of Physics Sapienza University of Rome Sapienza University of Rome Rome, Italy Rome, Italy IAC “Mauro Picone” CNR Pietro Greco Rome, Italy Città della Scienza Naples, Italy School of Physics University College of Dublin Dublin, Ireland Translated by Giuliana Giobbi Segreteria Scientifica INAF-OAR Osservatorio Astronomico di Roma Monte Porzio Catone, Italy G. Battimelli, G. Ciccotti, P. Greco: Il computer incontra la fisica teorica. La nuova frontiera della simulazione molecolare, Carocci editore, Roma (2020) ISSN 1612-3018 ISSN 2197-6619 (electronic) THE FRONTIERS COLLECTION ISBN 978-3-030-39398-4 ISBN 978-3-030-39399-1 (eBook) https://doi.org/10.1007/978-3-030-39399-1 © Springer Nature Switzerland AG 2020 This work is subject to copyright. All rights are reserved by the Publisher, 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 any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. 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This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Preface The idea of this book first took shape in the head of one of the authors (GC) following a conversation with his late friend Pierre Turq, a chemist from Paris who was among the first scientists in France to foresee the potentialities of computer simulation for the development of his own discipline. We wondered what, if any, mysterious reasons lay behind the fact that the epistemological upheaval brought by molecular simulation techniques into physical chemistry had never found a coun- terpart in some form of public exposition aimed at telling its history and explaining its relevance. Pierre felt that this circumstance was rooted in a sort of reluctance, by the chemistry community, to critically consider, and give a public account of, its own history. In so doing, chemistry would thereby admit, in the epistemological hierarchy of scientific disciplines, its subordinate position to physics, whose practitioners on the contrary have always been rather keen to give a public image of their science as the one best able to handle those problems that most deserve critical attention and historiographical scrutiny. This seemed to be a puzzling contradiction, given that, even at the time of this conversation, simulation had long since asserted itself as a pervasive approach in all fields of theoretical physics, in spite of the fact that its roots, and its first founding fathers, were rather to be found in physical chemistry. The inconsequence of the circumstance was manifest: the creation of a growing set of ideas, techniques, and potentialities that had come to pervade the whole field of fundamental research, redefining the canonical boundaries between contiguous disciplines and radically altering their cognitive procedures, had been substantially ignored as a subject worthy of critical inquiry and public exposition because its origins were not deemed noble enough. An original sin condemning it to oblivion. This seems all the more paradoxical because in the meantime the novelties brought about by the intensive use of computers have not been confined to the emergence of a new way of doing theoretical physics, and to its extension to research fields traditionally regarded as being outside the dominion of the “hard” sciences (such as biology or pharmaceutical chemistry), but have also produced a significant impact on mathematics, giving birth to new sectors of applied mathematics v vi Preface concerned with numerical analysis, mathematical statistics, and construction of the increasingly sophisticated algorithms needed for intensive computation. Only in recent times have a few research projects on the history and assessment of simulation seen the light, along with a few works of historiographical analysis; they have, however, been confined to the academic environment and have in no way contributed to modifying the substantial ignorance on the matter in the wider scientific culture. Be this as it may, the final result is that an outstanding innovation in the practice of fundamental research, one that has substantially reshuffled the traditional disciplinary hierarchies, has grown up and established itself without a collective perception of that novelty in the image of science. This book is an attempt to obviate this incongruence. We thought that the optimal way to proceed would be to present the reader with the historical devel- opment of this transformation, by keeping technical matters down to the indis- pensable minimum, and ending our narration at the moment when it can be considered that the potentialities emerging with the birth of molecular simulation, around the mid-50s, were fully expressed, and the development of the sector had given rise to a clearly defined discipline with its own identity; our reconstruction therefore stops at the end of the 80s, when this first phase of the history of molecular simulation reached its completion. Rome, Italy Giovanni Battimelli Rome, Italy Giovanni Ciccotti Naples, Italy Pietro Greco Acknowledgements Right through this work, we have been helped in various ways by so many friends and colleagues that we have almost certainly overlooked some names; we apologize in advance for any omission. We thank in particular Alin Elena for his careful reading of the text; Sara Bonella, Daniel Borgis, Ignacio Pagonabarraga, Benjamin Rotenberg, and Rodolphe Vuilleumier for their continuous support of the initiative; Mauro Ferrario for being systematically available to help; and Carlo Pierleoni for helping to orient us in the intricacies of the physics questions related to quantum Monte Carlo. Among the protagonists of our history, we have received useful informations and suggestions from Charles Bennett, Jean-Pierre Hansen, Ray Kapral, Mike Klein, Michel Mareschal, Ian McDonald, Thanos Panagiotopoulos, Daniel Schiff, and Glenn Torrie. For the reconstruction of the origins of our history, we have profited invaluably from the long interaction with Berni Alder. We are particularly indebted to Hans Christian Andersen, Kurt Binder, David Ceperley, Daan Frenkel, Mal Kalos, Dominique Levesque, and Mary Ann Mansigh; beside sending precious comments, they have repeatedly intervened directly in our original version, greatly improving the readability of the text and correcting slips and inaccuracies; Daan, in particular, deserves our gratitude for his systematic presence and support all along our adventure. It goes without saying that we take full responsibility for any remaining faults and omissions still present in the text.