2011/11/21 by Daniel Conus, Conus, Daniel, Mathew Joseph +5 · 1 citation
Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Mathematics #Probability (math.PR) #Stochastic processes and statistical mechanics #Theoretical and Computational Physics
paper · pdf · doi:10.48550/arxiv.1111.4728
openalex publication_date 2011/11/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Consider the stochastic heat equation ∂t u = ((\varkappa)/(2))Δu+σ(u)F, where the solution u:=ut(x) is indexed by (t,x)∈ (0, ∞)×\Rd, and F is a centered Gaussian noise that is white in time and has spatially-correlated coordinates. We analyze the large-|x| fixed-t behavior of the solution u in different regimes, thereby study the effect of noise on the solution in various cases. Among other things, we show that if the spatial correlation function f of the noise is of Riesz type, that is f(x)∝ ‖x‖-α, then the "fluctuation exponents" of the solution are ψ for the spatial variable and 2ψ-1 for the time variable, where ψ:=2/(4-α). Moreover, these exponent relations hold as long as α∈(0, d\wedge 2); that is precisely when Dalang's theory implies the existence of a solution to our stochastic PDE. These findings bolster earlier physical predictions.