Dinâmica de populações: modelo predador-presa estocástico e difusivo em um reticulado / Dynamic population: Predator-prey stochastic and difusive model on a lattice

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

We have studied the predator-prey stochastic model defined on a lattice with first neighbour interactions. Each site of the lattice may assume one of three states: vacant, occupied by prey and occupied by predator. We have introduced a parameter that controls the possibility of difusion among sites. The model shows an oscilating phase, a non-oscilating phase and an absorbing phase. In the first two phases the system exhibits coexistence of biological species while in the absorbing phase the lattice is filled with prey and the system becomes trapped. We have determined the transition line between the non-oscilating and absorbing phases using time-dependent simulations. We have also determined the transition lines between oscilating and non-oscilating phases using time-autocorrelation functions of the prey time-series. In addition, we have studied the model by means of dynamical mean-field aproximations. We conclude that the introduction of diffusion in the predator-prey model leads to a larger region of coexistence in the phase diagram. Our results suggest that difusion is irrelevant for the critical behavior since it does not change the universatility class of the model.

ASSUNTO(S)

método de monte carlo dinâmica de populações. processo estocástico dynamic population. phase transitions physic mudança de fase física stochastic process monte carlo method

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