title: Ensemble renormalization group for the random-field hierarchical model.
abstract: The renormalization group (RG) methods are still far from being completely understood in quenched disordered systems. In order to gain insight into the nature of the phase transition of these systems, it is common to investigate simple models. In this work we study a real-space RG transformation on the Dyson hierarchical lattice with a random field, which leads to a reconstruction of the RG flow and to an evaluation of the critical exponents of the model at T=0. We show that this method gives very accurate estimations of the critical exponents by comparing our results with those obtained by some of us using an independent method.
authors.affiliation: Dipartimento di Fisica, Università La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Decelle
authors.affiliation: Dipartimento di Fisica, Università La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma and INFN-Sezione di Roma 1 and CNR-IPCF, UOS di Roma, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Parisi
authors.affiliation: Dipartimento di Fisica, Università La Sapienza, Piazzale Aldo Moro 5, I-00185 Roma.
authors.forename: Jacopo
authors.initials: J
authors.lastname: Rocchi