We studied two models of three-species two-particle diffusion-limited reactions with and without a drift. Model A involves annihilations A+B→0, B+C→0, and C+A→0 with hard-core interactions between like species, and assumes equal initial densities of the species. The density decays...

The mA + nB → Ø diffusion limited reaction with homogeneous initial condition is studied analytically and numerically. Through renormalization group arguments, it is shiown that the system exhibits the anomalous kinetic behavior below the critical dimension dc∗ ≡ 4/(m + n − 1)....

We have studied diffusion-limited reaction on a one-dimensional lattice under the quenched disorder using Monte Carlo simulations. The hopping probabilities at a site is distributed by the power law p(y)=νyν−1 with 0<ν⩽1 and 0<y⩽1. The density of the reactants decays according to a power law, C(t)∼t−α(ν) for A+A→0 and A+B→0 annihilation reaction. The exponent α(ν) depends on the disorder exponent ν. For A+A→0, we have found α(ν)=ν/(1+ν). For A+B→0, we have observed α=0.25 at ν>0.4 and α decreases monotonically for α<0.4.

Starting from the well-known field theory for directed percolation (DP), we describe an evolving population, near extinction, in an environment with its own nontrivial spatio-temporal dynamics. Here, we consider the special case where the environment follows a simple relaxational (Model A)...

We investigate an epidemic spreading process by means of a computational simulation on the Apollonian network, which is simultaneously small-world, scale-free, Euclidean, space-filling and matching graphs. An analysis of the critical behavior of the Contact Process (CP) is presented using a...

We consider directed percolation with an absorbing boundary in 1 + 1 and 2 + 1 dimensions. The distribution of cluster lifetimes and sizes depend on the boundary. The new scaling exponents can be related to the exponents characterizing standard directed percolation 1 + 1 dimension. In addition,...

We introduce a model for the Contact Process with relaxing immunization CPRI. In this model, local memory is introduced by a time and space dependence of the contamination probability. The model has two parameters: a typical immunization time τ and a maximum contamination probability a. The...

A new position-space renormalization group approach is investigated for bond directed percolation in two dimensions. The threshold value for the bond occupation probabilities is found to be pc=0.6443. Correlation length exponents on time (parallel) and space (transverse) directions are found to...

A dimer–dimer reaction model of the type A2+B2→2AB is investigated by means of computer simulations. The desorption of B2 dimer with probability P is studied. Here we investigate the critical behaviour. The critical exponents of our model do not fall into the Reggeon field theory or directed...

We consider a version of directed bond percolation on a square lattice whose vertical edges are directed upward with probabilities pv and horizontal edges are directed rightward with probabilities ph and 1 in alternate rows. Let τ(M,N) be the probability that there is a connected directed path...