Superselection Rules
نویسنده
چکیده
This note provides a summary of the meaning of the term ‘Superselection Rule’ in Quantum Mechanics and Quantum-Field Theory. It is a contribution to the Compendium of Quantum Physics: Concepts, Experiments, History and Philosophy, edited by Friedel Weinert, Klaus Hentschel, Daniel Greenberger, and Brigitte Falkenburg.
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States, Symmetries and Superselection
The process of dynamical decoherence may cause apparent superselection rules, which are sometimes called ‘environmentally induced’ or ‘soft’. A natural question is whether such dynamical processes are eventually also responsible for at least some of the superselection rules which are usually presented as fundamentally rooted in the kinematical structure of the theory (so called ‘hard’ supersele...
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