Localizing Gravity and Supergravity on Braneworlds

Supergravity brane solutions provide a variety of contexts for effectively obtaining lower-dimensional physics within a higher-dimensional theory, but with noncompact transverse spaces instead of a usual Kaluza-Klein compactification. Two such contexts will be discussed. One is a promotion of the static "vacuum" brane solution to a full braneworld supergravity theory for the degree of supersymmetry possessed by the static brane. This allows for a "consistent truncation" brane supergravity ansatz in which the vacuum brane serves as a standard "skeleton" for embedding in the higher dimensional theory. The second is a more complete localization which exists in situations where the transverse wave equation spectrum starts with a normalizable zero mode state separated by a mass gap from the continuum expected in a noncompact transverse space. An example based on a transverse Eguchi-Hanson space will be discussed.