Boundary Conditions in Brane-World Supergravity

TL;DR

This paper discusses how boundary conditions in five-dimensional brane-world supergravity preserve supersymmetry and simplifies the description of supersymmetry breaking, especially in warped Randall-Sundrum models.

Contribution

It clarifies the role of boundary conditions in maintaining supersymmetry in brane-world supergravity and compares the 'downstairs' and 'upstairs' approaches, highlighting advantages of the former.

Findings

Boundary conditions are essential for supersymmetry preservation.

The 'downstairs' picture simplifies Scherk-Schwarz supersymmetry breaking.

Physics on the fundamental domain can be lifted to the upstairs picture with discontinuous fields.

Abstract

Bulk supergravity on a manifold with boundary must be supplemented by boundary conditions that preserve local supersymmetry. This "downstairs" picture has certain advantages over the equivalent "upstairs" picture, expressed in terms of orbifolds. In particular, Scherk-Schwarz supersymmetry breaking can be described much more simply in the downstairs picture. Nevertheless, physics on the fundamental domain can always be lifted upstairs, so long as fields are allowed to be discontinuous across the boundary. In this talk we apply these considerations to five-dimensional supergravity in a warped Randall-Sundrum background.