title: Contact process with sublattice symmetry breaking.
abstract: We study a contact process with creation at first- and second-neighbor sites and inhibition at first neighbors, in the form of an annihilation rate that increases with the number of occupied first neighbors. Mean-field theory predicts three phases: inactive (absorbing), active symmetric, and active asymmetric, the latter exhibiting distinct sublattice densities on a bipartite lattice. These phases are separated by continuous transitions; the phase diagram is re-entrant. Monte Carlo simulations in two dimensions verify these predictions qualitatively, except for a first-neighbor creation rate of zero. (In the latter case one of the phase transitions is discontinuous.) Our numerical results confirm that the symmetric-asymmetric transition belongs to the Ising universality class, and that the active-absorbing transition belongs to the directed percolation class, as expected from symmetry considerations.
authors.affiliation: Departamento de Física e Matemática, CAP, Universidade Federal de São João del Rei, 36420-000 Ouro Branco, Minas Gerais, Brazil. mmdeoliveira@ufsj.edu.br
authors.forename: Marcelo Martins
authors.initials: MM
authors.lastname: de Oliveira
authors.forename: Ronald
authors.initials: R
authors.lastname: Dickman
mesh_terms: D000042:Absorption; D000818:Animals; D001703:Biophysics / Q000379:methods; D003198:Computer Simulation; D006801:Humans; D015233:Models, Statistical; D008962:Models, Theoretical; D009010:Monte Carlo Method; D044367:Phase Transition; D010825:Physics / Q000379:methods*; D012160:Retina / Q000473:pathology; D013269:Stochastic Processes