Topological entanglement entropy in Chern-Simons theories and quantum Hall fluids

Abstract

We compute directly the entanglement entropy of spatial regions in Chern-Simons gauge theories in 2+1 dimensions using surgery. We consider the possible dependence of the entanglement entropy on the topology of the spatial manifold and on the vacuum state on that manifold. The entanglement entropy of puncture insertions (quasiparticles) is discussed in detail for a few cases of interest. We show that quite generally the topological entanglement entropy is determined by the modular -matrix of the associated rational conformal field theory as well as by the fusion rules and fusion coefficients. We use these results to determine the universal topological piece of the entanglement entropy for Abelian and non-Abelian quantum Hall fluids. As a byproduct we present the calculation of the modular -matrix of two coset RCFTs of interest.