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SUMMARY:Susskind and Uglum Revisited - Amr Ahmadain
DTSTART:20220602T120000Z
DTEND:20220602T130000Z
UID:TALK174569@talks.cam.ac.uk
CONTACT:Chiung Hwang
DESCRIPTION:In this talk\, I will give a brief overview of Susskind's and 
 Uglum's work with a special focus on their closed string off-shell derivat
 ion of the tree-level black hole entropy in a conical manifold.\n\nSince c
 onformal invariance is broken (due to the conical singularitiy)\, the nonl
 inear sigma model living on the worldsheet is a QFT rather than a CFT. Sus
 skind and Uglum used Tseytlin's nonlinear sigma model-based prescription f
 or constructing off-shell classical effective actions. Their calculation g
 ets the factor of 1/4 of the black hole entropy correct. \n\nI will briefl
 y mention some novel justifications for Tseytlin's sphere prescriptions\, 
 in particular\, how to use it to obtain (i) Witten's i\\varepsilon prescri
 ption for the Lorentzian S-matrix\, and time permitting (ii) the correct e
 quations of motion in Euclidean signature. This is based on work with Aron
  Wall.
LOCATION:Potter Room\, DAMTP
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