Entanglement between Two Interacting CFTs and Generalized Holographic Entanglement Entropy

In this paper we discuss behaviors of entanglement entropy between two interacting CFTs and its holographic interpretation using the AdS/CFT correspondence. We explicitly perform analytical calculations of entanglement entropy between two free scalar field theories which are interacting with each other in both static and time-dependent ways. We also conjecture a holographic calculation of entanglement entropy between two interacting $\mathcal{N}=4$ super Yang-Mills theories by introducing a minimal surface in the S${}^5$ direction, instead of the AdS${}_5$ direction. This offers a possible generalization of holographic entanglement entropy.