Fwd: [fm-all] Dr. Pinamonti: Seminar on "Quantum Spacetime and the Horizon Problem"

[Ludwik Dabrowski]

Dr. Nicola Pinamonti from Genova will deliver a seminar on

	 "Quantum space-time and the horizon problem"

         Thursday, December 1, 2:30pm, Room 132, SISSA

Abstract:

We shall discuss some properties of some spherically symmetric solutions
of semiclassical Einstein equations coupled to a scalar quantum massless
field.
If we impose the principle of gravitational stability against
localization of events, we notice that there is a lower bound (of the
order of Planck length) on the dimension of the region where an event
can be localized. In deriving this result, we shall not use concepts
like "energy" in combination with the Heisenberg principle and we shall
not make any linear approximation to Einstein equations.
In the second part of the talk,  this minimal length will be used in
order to estimate the role of space time non-commutativity in some
cosmological models possessing a Big Bang singularity. If radiation is
assumed to be in a thermal state, the arising scenario is similar
to a power law inflationary universe where the horizon problem disappears.