Gravitational Waves in a Codimension Two Braneworld

TL;DR

This paper studies gravitational wave propagation in a six-dimensional braneworld with de Sitter branes, showing low-energy gravity recovery and analyzing higher-dimensional corrections, including effects of brane regulation and Gauss-Bonnet terms.

Contribution

It provides an explicit calculation of gravitational wave corrections in a 6D warped braneworld with de Sitter branes, highlighting the role of cutoff dependence and the limitations of Gauss-Bonnet terms.

Findings

Low-energy gravity is recovered on the brane.

Leading six-dimensional corrections include a logarithmic cutoff dependence.

Gauss-Bonnet terms do not regulate codimension two branes in compact extra dimensions.

Abstract

We consider the propagation of gravitational waves in six dimensions induced by sources living on 3-branes in the context of a recent exact solution hep-th/0506050. The brane geometries are de Sitter and the bulk is a warped geometry supported by a positive cosmological constant as well as a 2-form flux. We show that at low energies ordinary gravity is reproduced, and explicitly compute the leading corrections from six dimensional effects. After regulating the brane we find a logarithmic dependence on the cutoff scale of brane physics even for modes whose frequency is much less than this energy scale. We discuss the possibility that this dependence can be renormalized into bulk or brane counterterms in line with effective field theory expectations. We discuss the inclusion of Gauss-Bonnet terms that have been used elsewhere to regulate codimension two branes. We find that such terms do not regulate codimension two branes for compact extra dimensions.