Gravitational wave propagation on the brane in different braneworld scenarios

Abstract

In this paper, we consider several well-known braneworld gravity scenarios such as the Rundall-Sundrum type II ( RSII ) theory, the Dvali, Gabadadze, and Porrati (DGP) braneworld, and the braneworld mimetic gravity. We then focus on studying the behavior of gravitational wave propagation on the brane in each setup. Using a specific approach and considering each setup’s brane separately, which requires distinct cosmological background, we show that different braneworld scenarios imply various amplitude and frequency reduction rates. By plotting the temporal part of the gravitational wave equation and comparing results, we deduce that the RSII braneworld scenario implies a more stable wave on its brane than the standard model. In the case of DGP gravity, we investigate the two branches separately and show that in the normal branch of this model, the amplitude and frequency of brane gravitational waves decay extremely fast.