SP Seminar @SISSA Via Bonomea 265, Tuesday 30 January at 11 am - Benoit ESTIENNE

[CM Section]

Joint ICTP/SISSA Statistical Physics Seminar

Tuesday 30 January at 11:00 a.m.
SISSA Via Bonomea 265, Room 128
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Speaker:
Benoit ESTIENNE (UPMC Paris, France)

Title:
Entanglement Entropies of 1d Critical Systems,Orbifold and Null-Vectors

Abstract:

  We present a new method to compute Renyi entropies in one-dimensional
  critical systems, using the mapping of the Nth Renyi entropy to a 
correlation
  function involving twist fields in a ZN cyclic orbifold. When the CFT 
describing
  the universality class of the critical system is rational, so is the 
corresponding
  cyclic orbifold. It follows that the twist fields are degenerate: they 
have null
  vectors. From these null vectors a Fuchsian differential equation is 
derived,
  although this step can be rather involved since the null-vector 
conditions
  generically involve fractional modes of the orbifold algebra. The last 
step
  is to solve this differential equation and build a monodromy invariant
  correlation function, which is done using standard bootstrap methods.
  This method is applicable in a variety of situations where no other method
   is available, for instance when the subsystem A is not connected (e.g.
  two-intervals EE).