On the intermittency front of stochastic heat equation driven by colored noises

We study the propagation of high peaks (intermittency front) of the solution to a stochastic heat equation driven by multiplicative centered Gaussian noise in $\mathbb{R}^d$. The noise is assumed to have a general homogeneous covariance in both time and space, and the solution is interpreted in the senses of the Wick product. We give some estimates for the upper and lower bounds of the propagation speed, based on a moment formula of the solution. When the space covariance is given by a Riesz kernel, we give more precise bounds for the propagation speed

Large time asymptotics for the parabolic Anderson model driven by spatially correlated noise

In this paper we study the linear stochastic heat equation, also known as parabolic Anderson model, in multidimension driven by a Gaussian noise which is white in time and it has a correlated spatial covariance. Examples of such covariance include the Riesz kernel in any dimension and the covariance of the fractional Brownian motion with Hurst parameter $H\in (\frac 14, \frac 12]$ in dimension one. First we establish the existence of a unique mild solution and we derive a Feynman-Kac formula for its moments using a family of independent Brownian bridges and assuming a general integrability condition on the initial data. In the second part of the paper we compute Lyapunov exponents, lower and upper exponential growth indices in terms of a variational quantity. The last part of the paper is devoted to study the phase transition property of the Anderson model

Stochastic partial differential equations driven by colored noise

This dissertation studies some problems for stochastic partial differential equations, in particular, (nonlinear) stochastic heat and stochastic wave equations, driven by (multiplicative) colored Gaussian noises. These problems considered are existence and uniqueness of the solution, Hölder continuity of the solution, Feynman-Kac formula for the solution, Feynman-Kac formula for the moments of the solution, Smoothness of the density of the solution as a random vectors at different spatial locations, intermittency (asymptotics for the high moments of the solution)