Entanglement Islands in Braneworlds

Entanglement island is a recently emergent concept playing an important role in resolving the black hole information paradox. In these resolution proposals the black hole is coupled to a bath which absorbs the radiation from the black hole and we can calculate the entanglement entropy of the black hole radiation as a function of time by studying the bath. The results are consistent with Page's argument that the entanglement entropy versus time diagram obeys unitarity– a Page curve. In higher dimensions, this calculation of the Page curve can be done only in braneworld models. More precisely, the Karch-Randall braneworld models and for AdS black holes. A closer look at the braneworld models tells us that the graviton is massive as the massless graviton mode is not normalizable. However, this effect of having a massive graviton is induced by coupling the black hole to a bath which is a universal feature of all the resolution proposals in higher dimensions. Several attempts to construct entanglement islands for massless gravity using braneworld give us many interesting new setups to study quantum gravity– including a codimension two holography in AdS (wedge holography) and Page curve for de Sitter radiation. Though these attempts didn't provide us with entanglement islands for massless gravity in asymptotically AdS spaces. We will see that a more careful study tells us that in a large set of situations entanglement islands don't exist in massless gravity theories. In the talk I will give a complete review of this line of research.