Quantum Objects: Non-Local Correlation, Causality and Objective Indefiniteness in the Quantum World PDF
Preview Quantum Objects: Non-Local Correlation, Causality and Objective Indefiniteness in the Quantum World
Fundamental Theories of Physics 175 Gregg Jaeger Quantum Objects Non-Local Correlation, Causality and Objective Indefi niteness in the Quantum World Fundamental Theories of Physics Volume 175 Series Editors HenkvanBeijeren,UtrechtUniversity,Utrecht,TheNetherlands PhilippeBlanchard,Universita¨tBielefeld,Bielefeld,Germany PaulBusch,UniversityofYork,Heslington,York,UnitedKingdom BobCoecke,OxfordUniversityComputingLaboratory,Oxford,UnitedKingdom DetlefDu¨rr,MathematischesInstitut,Mu¨nchen,Germany RomanFrigg,LondonSchoolofEconomicsandPoliticalScience,London,UnitedKingdom ChristopherA.Fuchs,PerimeterInstituteforTheoreticalPhysics,Waterloo,Canada GiancarloGhirardi,UniversityofTrieste,Trieste,Italy DomenicoGiulini,UniversityofHannover,Hannover,Germany GreggJaeger,BostonUniversityCGS,Boston,USA ClausKiefer,UniversityofCologne,Cologne,Germany KlaasLandsman,RadboudUniversiteitNijmegen,Nijmegen,TheNetherlands ChristianMaes,K.U.Leuven,Leuven,Belgium HermannNicolai,Max-Planck-Institutfu¨rGravitationsphysik,Golm,Germany VesselinPetkov,ConcordiaUniversity,Montreal,Canada AlwynvanderMerwe,UniversityofDenver,Denver,USA RainerVerch,Universita¨tLeipzig,Leipzig,Germany ReinhardWerner,LeibnizUniversity,Hannover,Germany ChristianWu¨thrich,UniversityofCalifornia,SanDiego,LaJolla,USA DennisDieks,UtrechtUniversity,Utrecht,TheNetherlands Forfurthervolumes: http://www.springer.com/series/6001 Gregg Jaeger Quantum Objects Non-Local Correlation, Causality and Objective Indefiniteness in the Quantum World 123 GreggJaeger NaturalSciencesandMathematics BostonUniversity Boston USA ISBN978-3-642-37628-3 ISBN978-3-642-37629-0(eBook) DOI10.1007/978-3-642-37629-0 SpringerHeidelbergNewYorkDordrechtLondon LibraryofCongressControlNumber:2013947463 (cid:2)c Springer-VerlagBerlinHeidelberg2014 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. 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Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) To myparents. Preface The conceptual elements of quantum theory that now underlie our picture of the physical world include objective chance, quantum interference, and the objective indefiniteness of dynamical quantities. Quantum interference, which is directly observable,wasreadilyabsorbedbythephysicscommunity.Objectivechanceand indefiniteness, being of more philosophical significance, gained acceptance only after much debate and conceptualanalysis, when it was recognizedthat observed phenomena are better understood through these notions than through older ones or hidden variables. Of the results understood via these notions, the failure of quantumsystemsalwaystoobeytheconstraintofBell’sinequalityanditstestable successor,theCHSHinequality,hasbeenthemostdecisive.Theseinequalitiesare now recognized as central results not only of quantum theory but of physics as a whole. They concern the strength of correlations between properties of physical systems that are expected given the finiteness of the speed of light and common experience but are found not to encompass all of those found in the extended rangeofexperiencerecentlyattainedbyscience,whichnowreachesfarbeyondthe familiar.Thesenewobservationsbreachedtheconceptualcoreofphysicsinaway thatdecadesofpreviousargumentstotheeffectthatQuantummechanicsgivesrise toparadoxhadnot,becausenon-localpropertycorrelationswereshowntoconflict withthedeepestclassicalmechanicalnotionsratherthanjustexplainingparticular anomalies.The success of quantumtheorystronglyurgesus to acceptthe notions mentioned above and others which require the modification of our conception of whatagenericphysicalobjectisandhowitcanbe. Earlier discussions and surprising results of quantum theory did not lead to such a thoroughgoingquestioning of cherished notions regarding the content and structure of the world, being typically limited to processes occurring at atomic scales. Those previousresults conflicted primarilywith commonsense or showed only the inadequacy of particular laws or rules rather than of our basic notions regarding physical existence. It is for this reason that the question, for example, of which position was victorious in the Bohr–Einstein debates over the viability ofthethennewlyformulatedquantumtheorywasandisnotwidelyconsideredas significant, for example, as that between the Ptolemaic and Copernican positions. vii viii Preface However, the transition to the quantum world picture must be seen as at least as significant as the transition to Copernican cosmology as grounded in Newtonian mechanicsortotheacceptanceofbiologicalevolutionatthespecieslevel. In the wake of the Bohr–Einstein debate, a more penetrating conservative response to those physicists who were content with early quantum theory was mounted by Einstein, Podolsky, and Rosen (EPR). The argument was relatively more philosophical than previous ones and made explicit several conditions that had arguably been implicit in the foundation of classical theory; it pointed out a conflict between these conditions and behavior predicted by Quantum mechanics for a pair of particles in a specific quantum state. The argument of EPR later led John Bell more or less directly to his inequality, because it pointed directly to an example of classically inexplicable behavior within an extended bipartite physical system: The Bell inequality quantitatively demarcated a boundary of classicallyexplicablebehaviorthatistrespassedinQuantummechanics,providing a generalizable distinction between classical mechanical and extreme quantum mechanical correlations. It also proved less obscure to many than both the EPR argumentand the reasoningof Bohr by makingno use of terms such as reality or phenomenon. The EPR paper itself had already prompted Schro¨dinger to produce his own touchstone articles on the predictions of quantum theory and its relationship to space-time,whichalsoincludedhisfamouscatexampleandforthefirsttimeclearly defined and named the characteristic feature associated with distinctly quantum correlations:entanglement.EvenbeforetheEPRarticle,BohrandHeisenberghad begun emphasizing the limitations inherent in the joint specification of physical quantitiesinthequantumworldthatchallengedthosenaiveformsofmetaphysical realismwhichcouldcomfortablybeheldtogetherwithclassicalphysics.Through a series of incisive inquiries, beginning with this earlier work and leading to experimentaltestingofthevalidityofBell-typeinequalities,itbecameentirelyclear tophysiciststhatthenoveltiesofquantumtheoryinvolvemorethanthediscreteness of basic physicalquantitiesand differencesin predictionson the merely technical level,forexample,ofatomicspectraldistributions. Attempts to produce a satisfying corresponding worldview began with their appearance and have continued, with quanta being increasingly central to this picture.Theinvestigationoftheunderlyingcharacteristicsofquantumsystems—the pervasivenessofpropertyindefinitenessandextremelystrongpropertycorrelation at non-local spatiotemporal separations—have also provided a context for the emergence of quantum information science, to which some now look for a new quantum perspective. The associated questions of the implications of quantum mechanicsfortheconceptionofphysicalobjectsin space-timeandof theformof causationappropriatetothequantumworldaretheprimarysubjectsofthisbook. Lexington,USA GreggJaeger 2012 Acknowledgement I thank Claus Ascheron at Springer–Heidelberg for encouraging me to write this book as well as my research collaborators, particularly Paul Busch, Mauro D’Ariano,SahotraSarkar,andAlexanderSergienko,fortheintellectualstimulation relatingtovarioustopicsdiscussedhereandfortheirfriendship. ix
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