Why there is no information loss

          @misc{ scivideos_PIRSA:08120016,
            doi = {10.48660/08120016},
            url = {https://pirsa.org/08120016},
            author = {Ashtekar, Abhay},
            keywords = {Quantum Gravity},
            language = {en},
            title = {Why there is no information loss},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2008},
            month = {dec},
            note = {PIRSA:08120016 see, \url{https://scivideos.org/pirsa/08120016}}
          }
          

Abstract

Using 2-dimensional CGHS black holes, I will argue that information is not lost in the Hawking evaporation because the quantum space-time is significantly larger than the classical one. I will begin with a discussion of the conceptual underpinnings of problem and then introduce a general, non-perturbative framework to describe quantum CGHS black holes. I will show that the Hawking effect emerges from it in the first approximation. Finally, I will introduce a mean field approximation to argue that, when the back reaction is included, future null infinity is `long enough\' to capture full information contained in pure states at past null infinity and that the S-matrix is unitary. There are no macroscopic remnants.