Boundary Terms in Brane Worlds

TL;DR

This paper clarifies the relationship between orbifold and interval descriptions in 5D brane worlds, emphasizing the role of boundary terms and consistency conditions, especially in singular or infinite vacuum scenarios.

Contribution

It establishes a detailed correspondence between orbifold and interval pictures, including boundary terms and conditions, for both Z_2-even and Z_2-odd fields in 5D brane models.

Findings

Gibbons-Hawking terms are essential for consistency in the interval picture.

Boundary terms are derived for cases with naked singularities.

The paper shows how to handle infinite vacuum actions in brane setups.

Abstract

We clarify the relation between orbifold and interval pictures in 5d brane worlds. We establish this correspondence for Z_2-even and Z_2-odd orbifold fields. In the interval picture Gibbons-Hawking terms are necessary to fulfill consistency conditions. We show how the brane world consistency conditions arise in the interval picture. We apply the procedure to the situation where the transverse dimension is terminated by naked singularities. In particular, we find the boundary terms needed when the naive vacuum action is infinite.