Effects of mass media on opinion spreading in the Sznajd sociophysics model

In this work we consider the influence of mass media in the dynamics of the two-dimensional Sznajd model. This influence acts as an external field, and it is introduced in the model by means of a probability p of the agents to follow the media opinion. We performed Monte Carlo simulations on square lattices with different sizes, and our numerical results suggest a change on the critical behavior of the model, with the absence of the usual phase transition for p >similar to 0.18. Another effect of the probability p is to decrease the average relaxation times tau, that are log-normally distributed, as in the standard model. In addition, the tau values depend on the lattice size L in a power-law form, tau similar to L-alpha, where the power-law exponent depends on the probability p. (C) 2011 Elsevier B.V. All rights reserved.