Quantum States of the Spacetime, and Formation of Black Holes in AdS

We argue that a nonperturbative description of quantum gravity should involve two (noninteracting) copies of a dual field theory on the boundary, and describe the states of the spacetimes accordingly. So, for instance, a complete description of the asymptotically Anti-de-Sitter (AdS) spacetimes is given by two copies of the conformal field theory (CFT) associated to the global AdS spacetime. We also argue that, in this context, gravitational collapse and formation of a black hole may be described by unitary evolution of the dual nonperturbative degrees of freedom.