arXiv subjects

H. Collins

Publications and source records attributed to H. Collins.

2 recordsLinked to original sources

arXiv2000

Brane Cosmologies without Orbifolds

We study the dynamics of branes in configurations where 1) the brane is the edge of a single anti-de Sitter (AdS) space and 2) the brane is the surface of a vacuum bubble expanding into a Schwarzschild or AdS-Schwarzschild bulk. In both cases we find solutions that resemble the standard Robertson-Walker cosmologies although in the latter, the evolution can be controlled by a mass parameter in the bulk metric. We also include a term in the brane action for the scalar curvature. This term adds a contribution to the low energy theory of gravity which does not need to affect the cosmology but which is necessary for the surface of the vacuum bubble to recover four dimensional gravity.

hep-ph↗

arXiv2000

Linearized Gravity about a Brane

We use the Israel condition to treat carefully the weak-field perturbations due to the presence of matter on a 3-brane embedded between two regions of anti-de Sitter (AdS) space with different curvature lengths. A four dimensional Newton's Law only emerges at distances that are large compared to the AdS lengths. When a scalar curvature is included in the brane action, however, it is possible to generate a four dimensional theory of gravity even when one or both of the AdS lengths is large compared to distances along the brane. In particular, we provide an example in which the AdS lengths can be larger than the millimeter experimental bound.

hep-th↗