Localization of Bulk Fields on AdS_4 Brane in AdS_5

TL;DR

This paper investigates how various bulk fields, including scalars, vectors, and gravitinos, can be naturally localized on an AdS_4 brane within AdS_5 space through gravitational interactions, without additional trapping mechanisms.

Contribution

It demonstrates that all bulk fields from scalars to gravitons can be confined to an AdS_4 brane via gravity alone, and finds specific zero mode solutions for vector and spinor fields.

Findings

Bulk fields are confined to the brane through gravity for small cosmological constant.

Zero mode solutions for vector fields satisfy box boundary conditions.

Spinor and gravitino zero modes are localized without mass terms or kink profiles.

Abstract

We study the localization of various bulk fields on an $AdS_4$ brane in $AdS_5$. In this case, for a small brane cosmological constant, all the bulk fields ranging from scalar to graviton are naturally confined to the brane only through the gravitational interaction. In particular, for the vector field we can find an interesting zero mode solution which satisfies the box boundary condition. In the cases of spin 1/2 spinor and 3/2 gravitino fields, the form of zero modes is very similar to as in a flat Minkowski brane, but they are trapped on the $AdS_4$ brane even without introducing a mass term with a 'kink' profile.