
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.

