## Illinois Journal of Mathematics

### On the association and central limit theorem for solutions of the parabolic Anderson model

#### Abstract

We consider large scale behavior of the solution set $\{u(t,x): x\in{\mathbf{Z^d}}\}$ of the parabolic Anderson equation \begin{eqnarray*} u(t,x)&=&1+\kappa\int_0^t\Delta u(s,x)\, ds \\ &&{}+\int_0^tu(s,x)\,\partial W_x(s),\quad x\in{\mathbf{Z^d}},t\ge0, \end{eqnarray*} where $\{W_x : x\in{\mathbf{Z^d}}\}$ is a field of i.i.d. standard, one-dimensional Brownian motions, $\Delta$ is the discrete Laplacian and $\kappa>0.$ We establish that the properly normalized sum, $\sum_{x\in\Lambda _L}u(t,x),$ over spatially growing boxes $\Lambda_L=\{x\in{\mathbf {Z^d}}:\Vert x\Vert<L\}$ has an asymptotically normal distribution if the box $\Lambda_L$ grows sufficiently quickly with $t$ and provided $\kappa$ is sufficiently small depending on dimension. The asymptotic distribution of properly normalized sums over spatially growing disjoint boxes $\Lambda^1_L,\Lambda^2_L$ is asymptotically independent. Thus, on sufficiently large scales the field of solutions averaged over disjoint large boxes looks like an i.i.d. Gaussian field. We identify the variance of this Gaussian distribution in terms of the eigenfunction of the positive eigenvalue of the operator $2\kappa\Delta+\delta_0$.

#### Article information

Source
Illinois J. Math., Volume 54, Number 4 (2010), 1313-1328.

Dates
First available in Project Euclid: 24 September 2012

https://projecteuclid.org/euclid.ijm/1348505530

Digital Object Identifier
doi:10.1215/ijm/1348505530

Mathematical Reviews number (MathSciNet)
MR2981849

Zentralblatt MATH identifier
1260.60117

#### Citation

Cranston, M.; Mueller, G. On the association and central limit theorem for solutions of the parabolic Anderson model. Illinois J. Math. 54 (2010), no. 4, 1313--1328. doi:10.1215/ijm/1348505530. https://projecteuclid.org/euclid.ijm/1348505530

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