PIRSA:23040092 Scientific Series Quantum Fields and Strings

DOI10.48660/23040092

Series: Quantum Fields and Strings

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}}
}

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

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