Eur. Phys. J. B (2013) 86: 120
https://doi.org/10.1140/epjb/e2013-40031-6

Regular Article

Variational approximations for stationary states of Ising-like models

¹ Dipartimento di Scienza Applicata e Tecnologia, CNISM and Center for Computational Studies, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
² INFN, Sezione di Torino, via Pietro Giuria 1, 10125 Torino, Italy
³ Human Genetics Foundation, HuGeF, Via Nizza 52, 10126 Torino, Italy

^a e-mail: alessandro.pelizzola@polito.it

Received: 16 November 2012
Received in final form: 14 January 2013
Published online: 27 March 2013

Abstract

We introduce a new variational approach to the stationary state of kinetic Ising-like models. The approach is based on the cluster expansion of the entropy term appearing in a functional which is minimized by the system history. We rederive a known mean-field theory and propose a new method, here called diamond approximation, which turns out to be more accurate and faster than other methods of comparable computational complexity.