Black hole microstate cosmology

          @misc{ pirsa_19090109,
            doi = {10.48660/19090109},
            url = {https://pirsa.org/19090109},
            author = {Van Raamsdonk, Mark},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {Black hole microstate cosmology},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {sep},
            note = {PIRSA:19090109 see, \url{https://pirsa.org}}
          }
          

Abstract

In this talk we study a special class of high-energy states in holographic CFTs defined via Euclidean evolution from conformal boundary states. We argue that these are dual to black hole microstates with a geometrical behind-the-horizon region. We study the time-dependent physics of this behind-the-horizon region, whose ETW boundary geometry takes the form of a closed FRW spacetime. We show that in many cases, this behind-the-horizon physics can be probed directly by looking at the time dependence of entanglement entropy for sufficiently large spatial CFT subsystems. A fascinating possibility is that for certain states, we might have gravity localized to the ETW brane as in the Randall-Sundrum II scenario for cosmology. In this case, the effective description of physics beyond the horizon could be a big bang/big crunch cosmology of the same dimensionality as the CFT. In this case, the d-dimensional CFT describing the black hole microstate would give a precise, microscopic description of the d-dimensional cosmological physics.