Publications

Alex Kamenev

Download from http://link.aps.org/doi/10.1103/PhysRevE.74.041101

Abstract

Equilibrium phase transitions are associated with rearrangements of minima of a (Lagrangian) potential. Treatment of nonequilibrium systems requires doubling of degrees of freedom, which may be often interpreted as a transition from the ?coordinate?- to the ?phase?-space representation. As a result, one has to deal with the Hamiltonian formulation of the field theory instead of the Lagrangian one. We suggest a classification scheme of phase transitions in reaction-diffusion models based on the topology of the phase portraits of corresponding Hamiltonians. In models with an absorbing state such a topology is fully determined by intersecting curves of zero ?energy.? We identify four families of topologically distinct classes of phase portraits stable upon renormalization group transformations.