Heidelberg 2007 – scientific programme

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AKPhil: Arbeitskreis Philosophie der Physik

AKPhil 3: Quantum Cosmology 1

AKPhil 3.1: Talk

Tuesday, March 6, 2007, 16:45–17:15, KIP SR 3.401

The interpretation dilemma of a “quantum state of the universe” — •Helmut Fink — Institut f. Theoretische Physik I, Univ. Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen

The object system of quantum cosmology is the universe as a whole. Commonly, the state of a quantum system is used to make probabilistic predictions about the results of measurements at that system. Hence, the debate on whether there is a quantum ontology for individual systems without referring to relative frequencies of measurement results, is essential for the interpretation of a “quantum state of the universe”. As a consequence of the structure of quantum theory, implying several no-go theorems, we regard a classical conceptual frame as methodologically prior to every unique quantum description. Our conclusion is that a state can be either a proper quantum state or a state of the universe, but not both at the same time.

As a way out of this dilemma, the approach of consistent (or decoherent) quantum histories has been recommended. But quantum histories merely serve to illustrate the problem of non-unique correspondence between formalism and facts instead of solving it. If it is a methodological apriori of physics that at least some elements of the theoretical formalism can be uniquely related to some elements of a conceivable external reality, then the consistent histories approach is unacceptable.