Starts 30 Jan 2018 11:00
Ends 30 Jan 2018 12:00
Central European Time
SISSA, Via Bonomea 265, room 128
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).