# Local and gauge invariant observables in gravity

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Igor Khavkine

created by vitagliano on 27 Nov 2015

1 dec 2015
-- 15:00

Sala del Consiglio, DipMat, Università di Salerno

**Abstract.**

The notion of a local gauge invariant observable is central in the mathematical treatment of renormalization of interacting theories in Perturbative Algebraic Quantum Field Theory and the Functional approach to Classical Field Theory. Prototypical examples are compactly supported smearings of a scalar field, of a Maxwell field strength, or of an invariant polynomial in a Yang-Mills curvature. It is well known that observables of this type do not exist for General Relativity (GR). On the other hand, slightly relaxing the definition of locality opens the door to a large and explicit class of gauge invariant observables defined in terms of curvature scalars. This can be thought of as a new application of ideas that go back at least to Komar and Bergmann. I will briefly discuss rough ideas about the following properties of these observables: phase space and spacetime support, separation of generic and special solutions, calculation of Poisson brackets.