Probing the Meaning of Quantum Mechanics Superpositions, Dynamics, Semantics and Identity 10185_9789813146273_tp.indd 1 29/6/16 2:50 PM May2,2013 14:6 BC:8831-ProbabilityandStatisticalTheory PST˙ws TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk Probing the Meaning of Quantum Mechanics Superpositions, Dynamics, Semantics and Identity Quantum Mechanics and Quantum Information: Physical, Philosophical and Logical Approaches Cagliari, Italy 23 – 25 July 2014 Editors Diederik Aerts Brussels Free University (VUB), Belgium Christian de Ronde University of Buenos Aires, Argentina & Brussels Free University (VUB), Belgium Hector Freytes Università di Firenze, Italy Sven Aerts Università degli studi di Cagliari, Italy World Scientific NEW JERSEY • LONDON • SINGAPORE • BEIJING • SHANGHAI • HONG KONG • TAIPEI • CHENNAI • TOKYO 10185_9789813146273_tp.indd 2 29/6/16 2:50 PM Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. PROBING THE MEANING OF QUANTUM MECHANICS Superpositions, Dynamics, Semantics and Identity Copyright © 2016 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 978-981-3146-27-3 Desk Editor: Ng Kah Fee Typeset by Stallion Press Email: [email protected] Printed in Singapore KahFee - Probing the Meaning of Quantum Mechanics.indd 1 29-06-16 10:39:20 AM June30,2016 15:17 ProbingtheMeaningofQuantumMechanics:...-9inx6in b2515-fm pagev v EDITORIAL PREFACE Quantummechanicsisrecognizedtodayasoneofthemostsuccessfulphys- ical theories ever. However, its interpretation is still problematic, or more specifically,anunderstandingofwhatquantummechanicstalksaboutdoes notexistyet.Althoughthefeaturesthatareconsideredattheoriginofthese problems — Schr¨odinger’s cat situation, entanglement, non-separability and contextuality — are well identified and nowadays resources of well- established technical applications, we continue to lack a semantic and a conceptual representation explaining the relation of quantum theory to physical reality. Independently of the many developments in the 20th Century, dur- ing the last decades quantum mechanics has given rise to a new techno- logical era, a revolution taking place today especially within the field of quantuminformationprocessing,reachingfromquantumteleportationand cryptographyto quantumcomputation. This developmentis relatedto the philosophy of quantum mechanics which addresses epistemic and ontic in- terpretations, the meaning of individuality and identity, of quantum pos- sibility, objective probability and chance, free will and causality. Next to the philosophical foundations also the logical and mathematical structure of the theory is consideredinthe presentbook. The underlying mathemat- ical structure relatedto quantummechanics is basedonavectorialHilbert space, which was employed in 1932 by John von Neumann in his famous book Mathematical Foundations of Quantum Mechanics. Few years later, in 1936, John von Neumann and Garret Birkhoff published a seminal pa- per titled “The logic of quantum mechanics”. The subject of that paper was an investigation of the logical structure underlying the language of quantum mechanics, establishing a link between logic, language and quan- tum mechanics. From this standpoint several schools in the foundations of quantum mechanics and quantum logic with different approachesfollowed. June30,2016 15:17 ProbingtheMeaningofQuantumMechanics:...-9inx6in b2515-fm pagevi vi The differences in approach have still grown over time, up to the present day. The quantum logical approaches consider many different aspects of quantum mechanics such as: truth notions, the logic related to superpo- sitions and entanglement, modal approaches, logical systems associated to quantum computational gates and categorical approaches. These topics define a new extensive area of investigation in modern quantum logic and, at the same time, provide a deep contribution to the understanding of the theoryofquanta.Allthesedifferentsubjectsrelatedtoquantummechanics are discussed and analyzed in the present book. This book attempts to address foundational questions in an interdisci- plinary manner considering the physical, philosophical, mathematical and logical aspects of quantum mechanics. Going from philosophy of quan- tum mechanics to quantum logic, from categorical approaches to quantum informationprocessing,the originalityofthis bookresidesinthe multiplic- ity of approaches which focus on the common aim, to grasp the meaning of the theory of quanta. We believe that the advancement of such under- standing will be possible, not through the strict separation of smaller and smallersubjectsofresearch,butontheverycontrary,throughthecommon sharing and discussion of multiple perspectives that come from different fields. The novelty of the book comes from the multiple perspectives put for- ward by top researchers in quantum mechanics, from Europe as well as North and South America, discussing the meaning and structure of the theory of quanta. The book comprises in a balanced manner physical, philosophical, logicaland mathematical approachesto quantum mechanics andquantuminformation.Fromquantumsuperpositionsandentanglement to dynamics and the problem of identity, from quantum logic, computa- tion andquasi-settheoryto the categoryapproachandteleportation,from realism and empiricism to operationalism and instrumentalism, the book touches from different perspectives some of the most intriguing questions related to one of the most important physical theories of our time. From Buenos Aires to Brussels and Cagliari,from Florence to Florian´opolis, the interaction between different groups is reflected in the many different ar- ticles. This book is interesting not only to the specialists but also to the general public attempting to get a graspon some of the most fundamental questions of present quantum physics. D. Aerts, C. de Ronde, H. Freytes & R. Giuntini. June30,2016 15:17 ProbingtheMeaningofQuantumMechanics:...-9inx6in b2515-fm pagevii vii ACKNOWLEDGMENTS Thepresentbookwasinspiredbythefirsteditionoftheinternationalmeet- ing “Quantum Mechanics and Quantum Information: Physical, Philosoph- ical and Logical approaches” that took place at the University of Cagliari (Italy) in July 2014. We are particularly grateful to the Regione Sardegna that has par- tially supported this international meeting within the Regional project: “Modeling the uncertainty: Quantum Theory and Imaging Processing”, (Legge Regionale 7 Agosto 2007,n.7, Promozionedella ricerca scientifica e dell’innovazione tecnologica in Sardegna). A special thanks to the National Research Council CONICET (Argentina) and the Centre Leo Apostel CLEA(Bruxelles) that also spon- sored this conference. Last but not least, thanks to the Scientific Committee, composed of Diederik Aerts, Maria Luisa Dalla Chiara, Desio Crause and Newton da Costa,andtotheOrganizingCommittee,composedofChristiandeRonde, Hector Freytes, Giuseppe Sergioli and Antonio Ledda. Cagliari, May 13th, 2016 Roberto Giuntini May2,2013 14:6 BC:8831-ProbabilityandStatisticalTheory PST˙ws TThhiiss ppaaggee iinntteennttiioonnaallllyy lleefftt bbllaannkk June30,2016 15:17 ProbingtheMeaningofQuantumMechanics:...-9inx6in b2515-fm pageix ix CONTENTS 1. On the Notion of Truth in Quantum Mechanics: A Category-TheoreticStandpoint 1 V. Karakostas and E. Zafiris 2. A Logical Account of Quantum Superpositions 44 D. Krause and J. R. B. Arenhart 3. Mixing Categories and Modal Logics in the Quantum Setting 60 G. Cina` 4. Binary Gates in Three Valued Quantum Computational Logics 76 G. Sergioli, A. Ledda and R. Giuntini 5. The GTR-Model: A Universal Framework for Quantum-Like Measurements 91 D. Aerts and M. S. de Bianchi 6. ‘Probabilistic Knowledge’ as ‘Objective Knowledge’ in QuantumMechanics:PotentialImmanentPowersInstead of Actual Properties 141 C. de Ronde 7. On When a Semantics is not a Good Semantics: The Algebraisation of Orthomodular Logic 179 T. Kowalski, F. Paoli and R. Giuntini