What’s inside a BH?

          @misc{ pirsa_PIRSA:17110096,
            doi = {10.48660/17110096},
            url = {https://pirsa.org/17110096},
            author = {Brustein, Ramy},
            keywords = {Quantum Gravity},
            language = {en},
            title = {What{\textquoteright}s inside a BH?},
            publisher = {Perimeter Institute},
            year = {2017},
            month = {nov},
            note = {PIRSA:17110096 see, \url{https://pirsa.org}}
          }
          

Abstract

We propose that a large Schwarzschild black hole (BH) is a bound state of highly excited, long, closed strings just above the Hagedorn temperature. The effective free-energy density is expressed as a function of its entropy density and contains only linear and quadratic terms, in analogy with that of collapsed living polymers. Classically, the horizon of such BH’s is completely opaque, hiding any clues about the state and very existence of its interior. Quantum mechanically and in equilibrium, the situation is not much different: Hawking radiation will now be emitted, but it carries a minimal amount of information. The situation is significantly different when such a quantum BH is out of equilibrium. The BH can then emit ``supersized" Hawking radiation with a much larger amplitude than that emitted in equilibrium. The result is a new type of quantum hair that can reveal the state and composition of the BH interior to an external observer.