Interpolating between Space-like and Time-like Entanglement via Holography

Abstract: We study entanglement entropy for slab like regions in quantum field theories, using their holographic duals. We focus on the transition between space like and time like separations. By considering boosted subsystems in conformal and confining holographic backgrounds, we identify two classes of extremal surfaces: real ones (Type I) and complex surfaces (Type II). These interpolate between the usual Ryu Takayanagi prescription and its time like generalisations. We derive explicit expressions for the entanglement entropy in both conformal and confining cases. We discuss their behaviour across phase transitions and null limits. The interpolation between Type I and Type II surfaces reveals an analytic continuation of the extremal surface across the light cone. Our analysis also finds the existence of a Ryu Takayanagi surface (Type I) even for time like separations in the confining field theory case.