PIRSA:23040092

The Off-shell String Effective Action and Black Hole Entropy

Ahmadain, A. (2023). The Off-shell String Effective Action and Black Hole Entropy . Perimeter Institute. https://pirsa.org/23040092

Ahmadain, Amir. The Off-shell String Effective Action and Black Hole Entropy . Perimeter Institute, Apr. 25, 2023, https://pirsa.org/23040092 

          @misc{ pirsa_PIRSA:23040092,
            doi = {10.48660/23040092},
            url = {https://pirsa.org/23040092},
            author = {Ahmadain, Amir},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {The Off-shell String Effective Action and Black Hole Entropy },
            publisher = {Perimeter Institute},
            year = {2023},
            month = {apr},
            note = {PIRSA:23040092 see, \url{https://pirsa.org}}
          }

Amr Ahmadain

University of Cambridge

Talk number
PIRSA:23040092
Collection
Talk Type
Subject
Abstract

Taking string theory off shell requires breaking Weyl invariance on the worldsheet, i.e. the worldsheet theory is now a QFT instead of a CFT. I will explain Tseytlin’s first-quantized approach to taking the worldsheet theory off-shell in a consistent manner, with a particular emphasis on the subtleties involved in calculating the sphere amplitude. This approach allows for the derivation of a classical string action which gives rise to the correct equations of motion and S-matrix, to all orders in perturbation theory. 

I'll also explain the underlying conceptual structure of the Susskind and Uglum black hole entropy argument. There I will show explicitly how the classical (tree-level) effective action and entropy S = A/4G_N may be calculated from the sphere diagrams. 

Time permitting, I will discuss ongoing efforts to derive the Ryu-Takayanagi formula in string theory.

Based on arXiv:2211.08607 and arXiv:2211.16448. 

Zoom link:  https://pitp.zoom.us/j/93668017324?pwd=K2pxZEhjalRTWkVVbVRESCtRVDFmUT09