Macroscopic effects of the quantum trace anomaly: dark energy and condensate stars

by Emil Mottola

Friday 6 Nov 2009, 14:15 → 15:15 Europe/Zurich

Univ. de Geneve, Auditoire Stueckelberg, 24 quai E. Ansermet, CH-1211 Genève 4

The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. These correspond to new long range massless scalar degrees of freedom in gravity, not present in the classical Einstein theory. The effective action of low energy gravity in the standard model therefore contains additional massless scalar degrees of freedom which couple to classical sources, contribute to gravitational scattering process and can have long range gravitational effects. These macroscopic effects are significant in the vicinity of black hole event horizons, and in cosmology on the Hubble scale, where they can lead to substantial, nonlinear backreaction on the classical geometry. In particular they suggest a completely non-singular final state of gravitational collapse in which the classical black hole event horizon is replaced by a thin shell, and the interior is a vacuum condensate with dark energy equation of the state, p=-rho. The condensate star has a modest entropy and suffers from no information paradox. The implications of these ideas for cosmology and dark energy will be discussed as well, as time permits.