Vacuum expectation values from a variational approach

In this letter we propose to use an extension of the variational approach known as Truncated Conformal Space to compute numerically the Vacuum Expectation Values of the operators of a conformal field theory perturbed by a relevant operator. As an example we estimate the VEVʹs of all (UV regular) primary operators of the Ising model and of some of the Tricritical Ising Model when perturbed by any choice of relevant primary operators. We compare our results with some other independent predictions.