Correlation function of four spins in the percolation model

Abstract

By using the Coulomb gas technics we calculate the four-spin correlation function in the percolation q→1 limit of the Potts model. It is known that the four-point functions define the actual fusion rules of a particular model. In this respect, we find that fusion of two spins, of dimension Δσ=596, produce a new channel, in the 4-point function, which is due to the operator with dimension Δ=5/8.