We investigate a family of models described by two holographic CFT2​s
coupled along a shared interface. The bulk dual geometry consists of two
AdS3​ spacetimes truncated by a shared Karch-Randall end-of-the-world (EOW)
brane. A lower dimensional effective model comprising of JT gravity coupled to
two flat CFT2​ baths is subsequently realized by considering small
fluctuations on the EOW brane and implementing a partial Randall-Sundrum
reduction where the transverse fluctuations of the EOW brane are identified as
the dilaton field. We compute the generalized entanglement entropy for
bipartite states through the island prescription in the effective lower
dimensional picture and obtain precise agreement in the limit of large brane
tension with the corresponding doubly holographic computations in the bulk
geometry. Furthermore, we obtain the corresponding Page curves for the Hawking
radiation in this JT braneworld.Comment: 40 pages, 15 figure