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PIRSA:14090004

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https://pirsa.org/14090004

Observables and Change in Totally Constrained Systems

Thebault, K. (2014). Observables and Change in Totally Constrained Systems. Perimeter Institute for Theoretical Physics. https://pirsa.org/14090004

Karim Thebault Ludwig-Maximilians-Universität München (LMU)

Talk numberPIRSA:14090004
DOI10.48660/14090004
Source RepositoryPIRSA
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Talk Type Scientific Series
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Abstract

We isolate an important physical distinction between gauge symmetries which exist at the level of histories and states, and those which exist at the level of histories and not states. This distinction is characterised explicitly using a generalized Hamilton-Jacobi formalism within which a non-standard prescription for the observables of classical totally constrained systems is developed. These ideas motivate a `relational quantization' procedure which is different from the standard `Dirac quanization'. In particular, relational quantization of totally constrained systems leads to a formalism with superpositions of energy eigenstates and an enlarged set of quantum observables. These `Kucha\v{r} observables' can change independently of each other, and thus are associated with measurable quantities in excess of the `perennials' of the standard Dirac approach.