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Speaker: Nicola Pinamonti, U. Genova
Title: Influence of quantum matter fluctuations on the expansion parameter of timelike geodesics
Abstract: During this talk, we shall discuss the passive influence of quantum matter fluctuations on the expansion parameter of a congruence of timelike geodesics in a semiclassical regime. In particular, we shall see that the perturbations of this parameter can be considered to be elements of the algebra of matter fields at all perturbative order. Hence, once a quantum state for matter is chosen, it is possible to explicitly evaluate the amplitude of the geometric fluctuations. After introducing the formalism necessary to treat similar problems, we estimate the approximated probability of having a geodesic collapse in a flat spacetime due to those fluctuations. Starting from this, some estimate of the spacetime uncertainty relations will be given.
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