Island formula in Planck brane

Abstract

Abstract Double holography offers a profound understanding of the island formula by describing a gravitational system on AdSd coupled to a conformal field theory on ℝ1,d−1, dual to an AdSd+1 spacetime with an end-of-the-world (EOW) brane. In this work, we extend the proposal in [12] by considering that the dual bulk spacetime has two EOW branes: one with a gravitational system and the other with a thermal bath. We demonstrate an equivalence between this proposal and the wedge holographic theory. We examine it in both Anti-de Sitter gravity and de Sitter gravity by calculating the entanglement entropy of the Hawking radiation. Finally, we employ the doubly holographic model to verify the formula for the entanglement entropy in a subregion within conformally flat spacetime.