Change without time [Elektronische Ressource] : relationalism and field quantization / vorgelegt von Johannes Simon

Change Without TimeRelationalism and Field QuantizationDissertationzur Erlangung des Doktorgradesder Naturwissenschaften (Dr. rer. nat.)der naturwissenschaftlichen Fakult¨at II – Physikder Universit¨at Regensburgvorgelegt vonJohannes Simonaus Schwandorf2004Promotionsgesuch eingereicht am: 19.04.2004Die Arbeit wurde angeleitet von Prof. Dr. Gustav M. Obermair.Prufungsausschuss:¨Vorsitzender Prof. Dr. W. Prettl1. Gutachter Prof. Dr. G. M. Obermair2. Gutachter Prof. Dr. E. Wernerweiterer Prufer Prof. Dr. A. Schafer¨ ¨Tag der mu¨ndlichen Pru¨fung: 23.07.2004Tempus item per se non est [...]Titus Lucretius Carus [Car, 459 ff]PrefaceThisthesisstudiesthefoundationsoftimeinphysics. Itsoriginliesintheurgetounderstandthequantummeasurementproblem. Whiletheemergenceofclassical-itycanbewelldescribedwithinalgebraicquantummechanicsofinfinitesystems,this can be achieved only in infinite time. This led me to a study of quantum dy-namicsofinfinitesystems, whichturnedouttobefarlessuniquethaninthecaseoffinitelymanydegreesoffreedom. Indecidingonthecorrecttimeevolutionthequestion appears how time – or rather duration – is being measured. Traditionalquantum mechanics lacks a time observable, and for closed systems in an energyeigenstate duration is indeed meaningless. A similar phenomenon shows up ingeneral relativity, where absolute duration (as well as spatial distance) becomesmeaningless due to diffeomorphism invariance.