David Olson with Glenn Starkman

Cosmology with Vacuum Bubbles

Recently, there has been much excitement in the cosmology community over the results coming from surveys of Type Ia supernovae. These surveys seem to indicate that the rate of expansion of the universe (as measured by the relationship between the redshifts of the supernovae and their luminosity distances) is accelerating. These observations extend out to a redshift of approximately 1.2.     Recently, however, Starkman, Trodden and Vachaspati have shown that in order to conclude that this expansion is a sign that the universe is inflating one must first extend these observations at least to a redshift of 1.8. We will extend this previous work by considering a vacuum bubble embedded in a Tolman-Bondi space-time and looking at the coupled evolution of the bubble wall and the space-time metric. We will see how the expansion of the space in the interior of the bubble depends on the initial conditions of the bubble. We will also find the effects of the wall evolution on the Cosmic Microwave Background Radiation to determine what constraints, if any, the isotropy of the CMBR would place on the size of such a bubble and our location in it.