A free field perspective of λ-deformed coset CFT’s

Abstract

Abstract We continue our study of λ-deformed σ-models by setting up a $$ \frac{1}{k} $$ 1 k perturbative expansion around the free field point for cosets, in particular for the λ-deformed SU(2)/U(1) coset CFT. We construct an interacting field theory in which all deformation effects are manifestly encoded in the interaction vertices. Using this we reproduce the known β-function and the anomalous dimension of the composite operator perturbing away from the conformal point. We introduce the λ-dressed parafermions which have an essential Wilson- like phase in their expressions. Subsequently, we compute their anomalous dimension, as well as their four-point functions, as exact functions of the deformation and to leading order in the k expansion. Correlation functions with an odd number of these parafermions vanish as in the conformal case.