Modifications to holographic entanglement entropy in warped CFT

In [1] it was observed that asymptotic boundary conditions play an important role in the study of holographic entanglement beyond AdS/CFT. In particular, the RyuTakayanagi proposal must be modified for warped AdS(3) (WAdS(3)) with Dirichlet boundary conditions. In this paper, we consider AdS(3) and WAdS(3) with Dirichlet-Neumann boundary conditions. The conjectured holographic duals are warped conformal field theories (WCFTs), featuring a Virasoro-Kac-Moody algebra. We provide a holographic calculation of the entanglement entropy and Renyi entropy using AdS(3)/WCFT and WAdS(3)/WCFT dualities. Our bulk results are consistent with the WCFT results derived by CastroHofman-Iqbal using the Rindler method. Comparing with [1], we explicitly show that the holographic entanglement entropy is indeed affected by boundary conditions. Both results differ from the Ryu-Takayanagi proposal, indicating new relations between spacetime geometry and quantum entanglement for holographic dualities beyond AdS/CFT.