Title: Thermalization after holographic bilocal quench,
Abstract: We study thermalization in the holographic (1+1)-dimensional CFT after
simultaneous generation of two high-energy excitations in the antipodal points
on the circle. The holographic picture of such quantum quench is the creation
of BTZ black hole from a collision of two massless particles. We perform
holographic computation of entanglement entropy and mutual information in the
boundary theory and analyze their evolution with time. We show that
equilibration of the entanglement in the regions which contained one of the
initial excitations is generally similar to that in other holographic quench
models, but with some important distinctions. We observe that entanglement
propagates along a sharp effective light cone from the points of initial
excitations on the boundary. The characteristics of entanglement propagation in
the global quench models such as entanglement velocity and the light cone
velocity also have a meaning in the bilocal quench scenario. We also observe
the loss of memory about the initial state during the equilibration process. We
find that the memory loss reflects on the time behavior of the entanglement
similarly to the global quench case, and it is related to the universal linear
growth of entanglement, which comes from the interior of the forming black
hole. We also analyze general two-point correlation functions in the framework
of the geodesic approximation, focusing on the study of the late time behavior.