JOINT PARTICLE SEMINAR

Date: Wednesday,  27 October 2004 Time: 3:00 p.m.

Place: 4135 Frederick Reines Hall

Speaker: Dr. Michael Graesser, Caltech

Title:Anthropic Distribution for Cosmological Constant and Primoridal Density Perturbations

Abstract: The anthropic principle has been proposed as an explanation for the observed value of the cosmological constant. Here we revisit this proposal by allowing for variation between universes in the amplitude of the scale-invariant primordial cosmological density perturbations. We derive a priori probability distributions for this amplitude from toy inflationary models in which the parameter of the inflaton potential is smoothly distributed over possible universes. We find that for such probability distributions, the likelihood that we live in a typical, anthropically-allowed universe is generally quite small.

Host: A. Rajaraman