Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions

We consider a dynamical brane world in a six-dimensional spacetime containing a singularity. Using the Israel conditions we study the motion of a 4-brane embedded in this setup. We analyse the brane behaviour when its position is perturbed about a fixed point and solve the full nonlinear dynamics in the several possible scenarios. We also investigate the possible gravitational shortcuts and calculate the delay between graviton and photon signals and the ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed to match the version accepted in Class. and Quant. Gra