Escape and Finite-Size Scaling in Diffusion-Controlled Annihilation

Autor: Ben-Naim, E., Krapivsky, P. L.
Rok vydání: 2016
Předmět:
Zdroj: J. Phys. A 49, 504004 (2016)
Druh dokumentu: Working Paper
DOI: 10.1088/1751-8113/49/50/504004
Popis: We study diffusion-controlled single-species annihilation with a finite number of particles. In this reaction-diffusion process, each particle undergoes ordinary diffusion, and when two particles meet, they annihilate. We focus on spatial dimensions $d>2$ where a finite number of particles typically survive the annihilation process. Using the rate equation approach and scaling techniques we investigate the average number of surviving particles, $M$, as a function of the initial number of particles, $N$. In three dimensions, for instance, we find the scaling law $M\sim N^{1/3}$ in the asymptotic regime $N\gg 1$. We show that two time scales govern the reaction kinetics: the diffusion time scale, $T\sim N^{2/3}$, and the escape time scale, $\tau\sim N^{4/3}$. The vast majority of annihilation events occur on the diffusion time scale, while no annihilation events occur beyond the escape time scale.
Comment: 5 pages, 4 figures
Databáze: arXiv