Classicality without decoherence: A new approach?

The world around us appears classical despite the fact that the fundamental particles constituting this world behave quantum. What explains the absence of Schroedingers cat and other bizarre superpositions? The commonly accepted explanation for that conundrum invokes the concept of
decoherence, i.e., the loss of coherence in open quantum systems in some preferred basis (the "pointer basis"). But is this explanation satisfactory and exhaustive? After a brief discussion of the decoherence approach, I explain a new approach to classicality, which arises in isolated many-body quantum systems. There is no decoherence, no open system and no pointer basis in that approach. Instead, it is based on the eigenstate thermalization hypothesis and works for "slow" observables, a property which will be defined rigorously in the talk.
Host: Geza Giedke

Hybrid Seminar: Donostia International Physics Center


Philipp Strasberg, Universitat Autonoma de Barcelon, Spain

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