Presentacion mural: From microscopic to macroscopic dynamics in spin systems with two symmetric absorbing states

FEDERICO VAZQUEZ

Huelva

Conferencia; FisEs 2009; 2009

We propose a general approach to study spin models with two symmetricabsorbing states.  Starting from the microscopic dynamics on a squarelattice, we derive a Langevin equation for  the time evolution of themagnetization field, that successfully explains coarsening propertiesof a wide range of  nonlinear voter models and systems withintermediate states.  We find that the  macroscopic behavior onlydepends on the first derivatives of the spin-flip probabilities.Moreover, an  analysis of the  mean-field term reveals the three typesof transitions commonly observed in these systems -generalized voter,Ising and directed percolation-.  Monte Carlo simulations of the spindynamics qualitatively agree with theoretical predictions.