title: Critical behavior of the one-dimensional diffusive pair contact process.
abstract: The phase transition of the one-dimensional diffusive pair contact process is investigated by N cluster mean-field approximations and high precision simulations. The N=3,4 cluster approximations exhibit smooth transition line to absorbing state by varying the diffusion rate D with beta(2)=2 mean-field order parameter exponent of the pair density. This contradicts with former N=2 results, where two different mean-field behavior was found along the transition line. Extensive dynamical simulations on L=10(5) lattices give estimates for the order parameter exponents of the particles for 0.05<or=D<or=0.7. These data may support former two distinct class findings. However, the gap between low- and high-D exponents is narrower than previously estimated and the possibility for interpreting numerical data as a single class behavior with exponents alpha=0.21(1), beta=0.40(1) assuming logarithmic corrections is shown. Finite-size scaling results are also presented.
authors.affiliation: Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest, Hungary.
authors.forename: Géza
authors.initials: G
authors.lastname: Odor