COLLOQUIUM

 

17:00 (CET) May 11,  Prof. Dr. Claus Kiefer ( University of Cologne)

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DECOHERENCE IN QUANTUM MECHANICS AND QUANTUM COSMOLOGY

 

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How does the classical behaviour emerge in a world that is fundamentally described by quantum theory? The key to the answer is given by a process that was described for the first time in 1970- decoherence. Decoherence is the irreversible emergence of classical properties of a quantum system through the unavoidable interaction with its environment. In my talk, I give a general introduction into decoherence and present its most important theoretical and experimental applications. I discuss the situation in quantum mechanics including the relevance of decoherence for the interpretation of quantum theory. I then turn to quantum cosmology and explain how the classical appearance of the metric and matter fields can be understood in a theory of quantum gravity where arbitrary metric superpositions can occur. I also address the relevance of decoherence for the origin of the arrow of time.