A note on brane cosmology

We derive a new class of time-dependent solutions for the Randall-Sundrum model by patching together isometries broken by the brane. Solutions generated by generalized boosts along the fifth dimension are associated with localized gravity and lead to an effective Friedman equation on the brane with a scale factor exhibiting power law or exponential behaviour. The effective energy-density on the brane depends linearly on the brane tension.