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SUMMARY:Gabriel Wong (Fudan University)
DTSTART:20201123T160000Z
DTEND:20201123T170000Z
DTSTAMP:20260423T005822Z
UID:Kadanoff/22
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/Kadanoff/22/
 ">Entanglement entropy and edge modes in topological string theory</a>\nby
  Gabriel Wong (Fudan University) as part of Kadanoff seminars\n\n\nAbstrac
 t\nThe Ryu Takayanagi formula identifies the area of boundary anchored ext
 remal surfaces in AdS with the entanglement entropy of the boundary CFT. H
 owever the bulk microstate interpretation of the extremal area remains mys
 terious.  Progress along this direction requires understanding how to defi
 ne entanglement entropy in the bulk closed string theory.   As a toy model
  for AdS/CFT\, we study the entanglement entropy of closed strings in the 
 topological A model  in the context of Gopakumar Vafa duality.  We give a 
 self consistent factorization of the closed string Hilbert space which lea
 ds to string edge modes  transforming under a q-deformed surface symmetry 
 group.    Compatibility with this symmetry requires a  q-deformed definiti
 on of entanglement entropy.    Using the topological vertex formalism\, we
  define the Hartle Hawking state for the resolved conifold and compute its
  q-deformed entropy directly from the closed string reduced density matrix
 .  We find a match with a target space replica calculation using the propo
 sal of Susskind and Uglum.    We then apply the Gopakumar Vafa duality to 
  reproduce the closed string entropy from Chern Simons theory using the un
 -deformed definition of entanglement entropy.    Finally we relate non loc
 al aspects of our factorization map to analogous phenomenon recently found
  in JT gravity..\n
LOCATION:https://researchseminars.org/talk/Kadanoff/22/
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