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T H E F R O N T I E R S C O L L E C T I O N Anthony Aguirre Brendan Foster Zeeya Merali (Eds.) IT FROM BIT OR BIT FROM IT? On Physics and Information THE FRONTIERS COLLECTION Series editors Avshalom C. Elitzur Unit of Interdisciplinary Studies, Bar-Ilan University, 52900 Ramat-Gan, Israel e-mail: [email protected] Laura Mersini-Houghton Department of Physics, University of North Carolina, Chapel Hill, NC 27599-3255, USA e-mail: [email protected] T. Padmanabhan Inter University Centre for Astronomy and Astrophysics (IUCAA) Pune, India Maximilian A. Schlosshauer Department of Physics, University of Portland, Portland, OR 97203, USA e-mail: [email protected] Mark P. Silverman Department of Physics, Trinity College, Hartford, CT 06106, USA e-mail: [email protected] Jack A. Tuszynski Department of Physics, University of Alberta, Edmonton, AB T6G 1Z2, Canada e-mail: [email protected] Rüdiger Vaas Center for Philosophy and Foundations of Science, University of Giessen, 35394 Giessen, Germany e-mail: [email protected] THE FRONTIERS COLLECTION Series Editors A.C. Elitzur L. Mersini-Houghton T. Padmanabhan M.A. Schlosshauer M.P. Silverman J.A. Tuszynski R. Vaas The books in this collection are devoted to challenging and open problems at the forefront of modern science, 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 thedeeper implicationsandfascinating questions involved.Taken asa whole,theseriesreflectstheneedforafundamentalandinterdisciplinaryapproach to modern science. Furthermore, it is intended to encourage active scientists in all areas to ponder over important and perhaps controversial issues beyond their own speciality. Extending from quantum physics and relativity to entropy, conscious- ness 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 Forafulllistofpublishedtitles,pleaseseebackofbookorspringer.com/series/5342 Anthony Aguirre Brendan Foster (cid:129) Zeeya Merali Editors IT FROM BIT OR BIT FROM IT? On Physics and Information 123 Editors AnthonyAguirre ZeeyaMerali Department of Physics FoundationalQuestions Institute Universityof California New York, NY SantaCruz,CA USA USA Brendan Foster FoundationalQuestions Institute New York, NY USA ISSN 1612-3018 ISSN 2197-6619 (electronic) THE FRONTIERSCOLLECTION ISBN 978-3-319-12945-7 ISBN 978-3-319-12946-4 (eBook) DOI 10.1007/978-3-319-12946-4 LibraryofCongressControlNumber:2014957160 SpringerChamHeidelbergNewYorkDordrechtLondon ©SpringerInternationalPublishingSwitzerland2015 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart 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 dissimilarmethodologynowknownorhereafterdeveloped. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexempt fromtherelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthis book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained hereinorforanyerrorsoromissionsthatmayhavebeenmade. Printedonacid-freepaper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) Preface This book is a collaborative project between Springer and The Foundational Questions Institute (FQXi). In keeping with both the tradition of Springer’s FrontiersCollectionandthemissionofFQXi,itprovidesstimulatinginsightsintoa frontier area of science, while remaining accessible enough to benefit a non- specialist audience. FQXi is an independent, nonprofit organization that was founded in 2006. It aimstocatalyze,support,anddisseminateresearchonquestionsatthefoundations of physics and cosmology. The central aim of FQXi is to fund and inspire research and innovation that is integraltoadeepunderstandingofreality,butwhichmaynotbereadilysupported byconventionalfundingsources.Historically,physicsandcosmologyhaveoffered a scientific framework for comprehending the core of reality. Many giants of modernscience—suchasEinstein,Bohr,Schrödinger,andHeisenberg—werealso passionately concerned with, and inspired by, deep philosophical nuances of the novel notions of reality they were exploring. Yet, such questions are often over- looked by traditional funding agencies. Often, grant-making and research organizations institutionalize a pragmatic approach,primarilyfundingincrementalinvestigationsthatuseknownmethodsand familiar conceptual frameworks, rather than the uncertain and often interdisciplinary methods required to develop and comprehend prospective revolutions in physics and cosmology. As a result, even eminent scientists can struggle to secure fundingforsomeofthequestionstheyfindmostengaging,whileyoungerthinkers findlittlesupport,freedom,orcareerpossibilitiesunlesstheyhewtosuchstrictures. FQXi views foundational questions not as pointless speculation or misguided effort, but as critical and essential inquiry of relevance to us all. The Institute is dedicated to redressing these shortcomings by creating a vibrant, worldwide community of scientists, top thinkers, and outreach specialists who tackle deep questions in physics, cosmology, and related fields. FQXi is also committed to engaging with the public and communicating the implications of this foundational research for the growth of human understanding. v vi Preface Aspartofthisendeavor,FQXiorganizesanannualessaycontest,whichisopen toeveryone,fromprofessionalresearcherstomembersofthepublic.Thesecontests are designed to focus minds and efforts on deep questions that could have a pro- found impact across multiple disciplines. The contest is judged by an expert panel andupto20prizesareawarded.Eachyear,thecontestfeatureswelloverahundred entries, stimulating ongoing online discussion for many months after the close of the contest. We are delighted to share this collection, inspired by the 2013 contest, “It from Bit or Bit from It?” In line with our desire to bring foundational questions to the widest possible audience, the entries, in their original form, were written in a style that was suitable for the general public. In this book, which is aimed at an inter- disciplinaryscientificaudience,theauthorshavebeeninvitedtoexpandupontheir original essays and include technical detailsand discussion that may enhance their essays for a more professional readership, while remaining accessible to non- specialists in their field. FQXi would like to thank our contest partners: The Gruber Foundation, The John Templeton Foundation, and Scientific American. The editors are indebted to FQXi’s scientific director, Max Tegmark, and managing director, Kavita Rajanna, who were instrumental in the development of the contest. We are also grateful to Angela Lahee at Springer for her guidance and support in driving this project forward. 2014 Anthony Aguirre Brendan Foster Zeeya Merali Contents 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Anthony Aguirre, Brendan Foster and Zeeya Merali 2 “It from Bit” and the Quantum Probability Rule. . . . . . . . . . . . . 5 M.S. Leifer 3 It from Qubit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Giacomo Mauro D’Ariano 4 Drawing Quantum Contextuality with ‘Dessins d’enfants’. . . . . . . 37 Michel Planat 5 The Tao of It and Bit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Ovidiu Cristinel Stoica 6 Information-Based Physics and the Influence Network . . . . . . . . . 65 Kevin H. Knuth 7 Relative Information at the Foundation of Physics. . . . . . . . . . . . 79 Carlo Rovelli 8 Information and the Foundations of Quantum Theory. . . . . . . . . 87 Angelo Bassi, Saikat Ghosh and Tejinder Singh 9 An Insight into Information, Entanglement and Time. . . . . . . . . . 97 Paul L. Borrill 10 These from Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Yutaka Shikano vii viii Contents 11 Self-similarity, Conservation of Entropy/bits and the Black Hole Information Puzzle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 Douglas Singleton, Elias C. Vagenas and Tao Zhu 12 Spacetime Weave—Bit as the Connection Between Its or the Informational Content of Spacetime . . . . . . . . . . . . . . . 129 Torsten Asselmeyer-Maluga 13 Now Broadcasting in Planck Definition . . . . . . . . . . . . . . . . . . . . 143 Craig Hogan 14 Is Spacetime Countable?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Sean Gryb and Marc Ngui 15 Without Cause. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Mark Feeley 16 Reality, No Matter How You Slice It. . . . . . . . . . . . . . . . . . . . . . 181 Ken Wharton 17 Bit from It. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Julian Barbour 18 Contextuality: Wheeler’s Universal Regulating Principle . . . . . . . 213 Ian T. Durham 19 It from Bit from It from Bit ... Nature and Nonlinear Logic. . . . . 225 Wm. C. McHarris Titles in this Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Appendix: List of Winners. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239 Chapter 1 Introduction AnthonyAguirre,BrendanFoster andZeeyaMerali ‘Itfrombit’symbolizestheideathateveryitemofthephysical worldhasatbottom—ataverydeepbottom,inmost instances—animmaterialsourceandexplanation;thatwhatwe callrealityarisesinthelastanalysisfromtheposingofyes-no questionsandtheregisteringofequipment-evokedresponses;in short,thatallthingsphysicalareinformation-theoreticinorigin andthisisaparticipatoryuniverse. JohnArchibaldWheeler(1989) Over the past century, there has been a steady progression away from thinking about physics, at its deepest level, as a description of material objects and their interactions, and towards physics as a description of the evolution of information about, and in, the physical world. Information theory encompasses the apparently inherent probabilistic nature of quantum mechanics, our statistical understanding ofthermodynamicalsystems,andcomputerscience,wheretheencodingofdatais described classically using rules laid out by Claude Shannon. Recent years have seen an explosion of interest at the nexus of physics and information, driven by theinformationageinwhichweliveandbydevelopmentsinquantuminformation theoryandcomputerscience. Theideathatinformationismorefundamentalthanthematterthatconveysitwas famouslyencapsulatedbyphysicistJohnArchibaldWheelerinthephrase“Itfrom Bit”.Wheelerwasprofoundlyawareofthepeculiarrelationshipbetweeninforma- tion and the measurements made by observers of quantum systems: He proposed a“delayed-choiceexperiment”usinglight—whichhassincebeendemonstratedin the laboratory—in which it appears that choices made by an experimenter after a B A.Aguirre( ) DepartmentofPhysics,UniversityofCalifornia,SantaCruz,CA,USA e-mail:[email protected] B.Foster·Z.Merali FoundationalQuestionsInstitute,NewYork,NY,USA e-mail:[email protected] Z.Merali e-mail:[email protected] ©SpringerInternationalPublishingSwitzerland2015 1 A.Aguirreetal.(eds.),ItFromBitorBitFromIt?, TheFrontiersCollection,DOI10.1007/978-3-319-12946-4_1