Equations of motion as constraints: superselection rules, Ward identities
نویسندگان
چکیده
منابع مشابه
Superselection Rules
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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The evolution of both quantum and classical ensembles may be described via the probability density P on configuration space, its canonical conjugate S, and an ensemble Hamiltonian H̃[P, S]. For quantum ensembles this evolution is, of course, equivalent to the Schrödinger equation for the wavefunction, which is linear. However, quite simple constraints on the canonical fields P and S correspond t...
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We discuss the applicability of the programme of decoherence – emergence of approximate classical behaviour through interaction with the environment – to cases where it was suggested that the presence of symmetries would lead to exact superselection rules. For this discussion it is useful to make a distinction between pure symmetries and redundancies, which results from an investigation into th...
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We show that superselection rules do not enhance the information-theoretic security of quantum cryptographic protocols. Our analysis employs two quite different methods. The first method uses the concept of a reference system—in a world subject to a superselection rule, unrestricted operations can be simulated by parties who share access to a reference system with suitable properties. By this m...
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ژورنال
عنوان ژورنال: Journal of High Energy Physics
سال: 2017
ISSN: 1029-8479
DOI: 10.1007/jhep03(2017)136