Gravitational waves in a codimension two braneworld

Abstract

We consider the propagation of gravitational waves in six dimensions induced by sourcesliving on 3-branes in the context of a recent exact solution (Mukohyama et al 2005J. Cosmol. Astropart. Phys. JCAP07(2005)013). The brane geometries are de Sitter and thebulk is a warped geometry supported by a positive cosmological constant as well as a2-form flux. We show that at low energies ordinary gravity is reproduced, and explicitlycompute the leading corrections from six-dimensional effects. After regulating the brane wefind a logarithmic dependence on the cut-off scale of brane physics even for modes whosefrequency is much less than this energy scale. We discuss the possibility that thisdependence can be renormalized into bulk or brane counterterms in line with effectivefield theory expectations. We discuss the inclusion of Gauss–Bonnet terms thathave been used elsewhere to regulate codimension two branes. We find that suchterms do not regulate codimension two branes for compact extra dimensions.