Comportamento crítico da produção de entropia em modelos com dinâmicas estocásticas competitivas / Critical behavior of entropy production in models with competitive stochastic dynamics

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

25/04/2011

RESUMO

We study kinetic phase transitions and the critical behavior of the entropy production in spin models with nearest neighbor interactions subject to two Glauber dynamics, which simulate two thermal baths at different temperatures. In this way, it is assumed that the system corresponds to a continuous time Markov process which obeys the master equation. Thus, the system naturally reaches steady states, which can be equilibrium or nonequilibrium. The former corresponds exactly to the Ising model, which occurs since the system is in contact with only one of the reservoirs. In this case, there is a phase transition at the Curie temperature and the detailed balance surely holds. In the second case, the two thermal baths create a non trivial probability current only when microscopic reversibility is not verified. As a consequence, there is a positive entropy production in a non-equilibrium steady state. Pair approximations and Monte Carlo simulations are employed to evaluate the phase diagrams and the entropy production. Furthermore, we assume that the finite-size scaling theory can be applied to the model. These methods were able to predict the phase transitions undergone by the system. The exponents and the critical points were estimated by the numerical results. Our best estimates of critical exponents to the magnetization and susceptibility are = 0,124 (1) and = 1,76 (1), which allows us to conclude that our model belongs to the same class of Ising. This result refers to the principle of universality of the critical point, which is checked because our model has the same inversion symmetry of the Ising model. Moreover, the pair approximation also showed a singularity in the derivative of the entropy production at the critical point. And Monte Carlo simulations allow us to suggest that the divergence at the critical point is of the logarithmic type whose critical exponent is 1

ASSUNTO(S)

dinâmicas de glauber entropy production and classical statisticcal mechanics equação mestra glauber dynamics master equation mecânica estatística clássica phase transitions transição de fases e produção de entropia

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