On the extremization and stabilization of the size of extra dimensions

by Panagiota KANTI (CERN-TH)

Thursday 7 Mar 2002, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

By using the method of the derivation of the effective four-dimensional theory of the radion field, we determine the 'extremization' and 'stabilization' constraints that solutions with a static and stable, respectively, extra dimension must satisfy. We focus on the case of five-dimensional brane world models and present particular examples, including: 1) the Randall-Sundrum solution, which is shown to be an absolute saddle point of the radion effective potential, 2) a two-brane model with a stabilizing/destabilizing effect coming from the Casimir force between the two branes, 3) a two-positive-tension-brane model that turns out to be unstable - a bad omen for solutions accommodating solely positive-tension branes, and finally 4) a two-brane model with a bulk scalar field where it is shown that the existence of a bulk singularity, although a shielded one, can play an important role in the stabilization of the system. A similar analysis is performed in the case of higher-dimensional spacetime and conclusions on the stability of the whole or part of the internal spacetime are drawn.