• Corpus ID: 221516155

The critical one-dimensional multi-particle DLA

@article{Elboim2020TheCO,
  title={The critical one-dimensional multi-particle DLA},
  author={Dor Elboim and Danny Nam and Allan Sly},
  journal={arXiv: Probability},
  year={2020}
}

• Dor Elboim, Danny Nam, A. Sly
• Published 6 September 2020
• Mathematics
• arXiv: Probability

We study one-dimensional multi-particle Diffusion Limited Aggregation (MDLA) at its critical density $\lambda=1$. Previous works have verified that the size of the aggregate $X_t$ at time $t$ is $t^{1/2}$ in the subcritical regime and linear in the supercritical regime. This paper establishes the conjecture that the growth rate at criticiality is $t^{2/3}$. Moreover, we derive the scaling limit proving that
$$\big\{ t^{-2/3}X_{st} \big\}_{s\geq 0} \overset{d}{\rightarrow} \Big\{ \int_0^s Z_u du \Big\}_{s\geq 0}, $$ where the speed process $\{Z_t\}$ is a $(-\frac{1}{3})$-self-similar diffusion given by $Z_t = (3V_t)^{-2/3}$, where $V_t$ is the $\frac{8}{3}$-Bessel process.
The proof shows that locally the speed process can be well approximated by a stochastic integral representation which itself can be approximated by a critical branching process with continuous edge lengths. From these representations, we determine its infinitesimal drift and variance to show that the speed asymptotically satisfies the SDE $dZ_t = 2Z_t^{5/2}dB_t$. To make these approximations, regularity properties of the process are established inductively via a multiscale argument.