Cross-over between diffusion-limited and reaction-limited regimes in the coagulation-diffusion process

TL;DR

This paper investigates the transition from diffusion-limited to reaction-limited regimes in the coagulation-diffusion process by analyzing universal long-time behaviors on different lattice structures, revealing crossover scaling and corrections.

Contribution

It extends the analysis of the coagulation-diffusion process from a chain to the Bethe lattice, deriving crossover scaling functions and effective exponents.

Findings

Logarithmic corrections to scaling at the Bethe lattice.

Derived crossover scaling functions between chain and Bethe lattice.

Analogous results for time-integrated particle-density.

Abstract

The change from the diffusion-limited to the reaction-limited cooperative behaviour in reaction-diffusion systems is analysed by comparing the universal long-time behaviour of the coagulation-diffusion process on a chain and on the Bethe lattice. On a chain, this model is exactly solvable through the empty-interval method. This method can be extended to the Bethe lattice, in the ben-Avraham-Glasser approximation. On the Bethe lattice, the analysis of the Laplace-transformed time-dependent particle-density is analogous to the study of the stationary state, if a stochastic reset to a configuration of uncorrelated particles is added. In this stationary state logarithmic corrections to scaling are found, as expected for systems at the upper critical dimension. Analogous results hold true for the time-integrated particle-density. The crossover scaling functions and the associated effective exponents between the chain and the Bethe lattice are derived.