Branched polymers in the presence of impurities

We study branched polymers in the presence of impurities using the branched polymer growth model, which has been proposed by Lucena et al. [Phys. Rev. Lett. 72, 230 (1994)]. To avoid boundary effects we study the growth process in chemical l-space and determine the structural exponents dₗ, dₘᵢₙ, and {τ}. For d=2 (square lattice) and d=3 (simple cubic lattice) our results are based on numerical simulations, while for the Bethe lattice (d={∞}) the quantities of interest were obtained analytically. These results support our recent suggestion that on the critical line the branched polymers belong to the universality class of percolation. {} 1996 The American Physical Society.