Field transformation and Monte Carlo simulations

A new method to compute observables at many values of the parameters λ for a model with lattice action S(phi, λ) is described. After fixing a reference set λr of parameters, a single simulation is carried out by using a 'reference action' S(phir, λr) to generate configurations of the field phir. Then a suitable analytic transformation is performed from the configurations of phir to the ones corresponding to the action S(phi, λ). Such a transformation allows to obtain the observables for values of the parameters λ close to λr. I present studies on the reliability of the algorithm in the case of the phi4 model in 2 dimensions