Séminaire de Physique ThéoriqueWhy there is Something rather than Nothing: Origin of the cosmological constant and dark energy
Andrei Barvinsky (Lebedev Physics Institute, Moscow, Russia)
Wednesday 31 October 2007 14:00 - Tours - Salle 1180 (Bât E2)
The density matrix of the Universe for the microcanonical ensemble in quantum cosmology describes an equipartition in the physical phase space of the theory (sum over everything), but in terms of the observable spacetime geometry this ensemble is peaked about the set of recently obtained cosmological instantons limited to a bounded range of the cosmological constant. This suggests the mechanism of constraining the landscape of string vacua and a possible solution to the dark energy problem in the form of the quasi-equilibrium decay of the microcanonical state of the Universe.