Irreversible phase transitions driven by an oscillatory parameter in a far-from-equilibrium system - art. no. 036119

The dynamic response of a forest-fire model to the harmonic variation of an external parameter is studied by means of numerical simulations. Second-or der irreversible phase transitions driven by the harmonic input are reporte d. The location of such transitions depends on both the amplitude and perio d of the input signal. By means of epidemic studies the relevant critical e xponents can be determined, which allow us to place the reported transition s in the universality class of directed percolation. This conclusion is als o supported by a field theoretical calculation.