PIRSA:19100040

Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT

APA

Shahbazi-Moghaddam, A. (2019). Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT. Perimeter Institute. https://pirsa.org/19100040

MLA

Shahbazi-Moghaddam, Arvin. Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT. Perimeter Institute, Oct. 29, 2019, https://pirsa.org/19100040

BibTex

          @misc{ pirsa_19100040,
            doi = {},
            url = {https://pirsa.org/19100040},
            author = {Shahbazi-Moghaddam, Arvin},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {Ignorance is Cheap: From Black Hole Entropy To Energy-Minimizing States In QFT},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {oct},
            note = {PIRSA:19100040 see, \url{https://pirsa.org}}
          }
          

Abstract

Behind certain marginally trapped surfaces one can construct a geometry containing an extremal surface of equal, but not larger area. This construction underlies the Engelhardt-Wall proposal for explaining the Bekenstein-Hawking entropy as a coarse-grained entropy. The construction can be proven to exist classically but fails if the Null Energy Condition is violated. Here we extend the coarse-graining construction to semiclassical gravity. Its validity is conjectural, but we are able to extract an interesting nongravitational limit. Our proposal implies Wall’s ant conjecture on the minimum energy of a completion of a quantum field theory state on a halfspace. It further constrains the properties of the minimum energy state; for example, the minimum completion energy must be localized as a shock at the cut. We verify that the predicted properties hold in a recent explicit construction of Ceyhan and Faulkner, which proves our conjecture in the nongravitational limit.