Two different kinds of interactions between a ${ Z}_{ n}$-parafermionic and a Liouville field theory are considered. For generic values of $n$, the effective central charges describing the UV behavior of both models are calculated in the Neveu-Schwarz sector. For $n=2$ exact vacuum expectation values of primary fields of the Liouville field theory, as well as the first descendent fields are proposed. For $n=1$, known results for Sinh-Gordon and Bullough-Dodd models are recovered whereas for $n=2$, exact results for these two integrable coupled Ising-Liouville models are shown to exchange under a weak-strong coupling duality relation. In particular, exact relations between the parameters in the actions and the mass of the particles are obtained. At specific imaginary values of the coupling and $n=2$, we use previous results to obtain exact information about: (a) Integrable coupled models like Ising-${ \cal M}_{ p/p'}$, homogeneous sine-Gordon model $SU(3)_2$ or the Ising-XY model; (b) Neveu-Schwarz sector of the $\Phi_{ 13}$ integrable perturbation of N=1 supersymmetric minimal models. Several non-perturbative checks are done, which support the exact results.
Categories: hep-th cond-mat math-ph math.MP