Pathological Large Deviations of the KMP Process in Dimension $d\ge 2$

Abstract

We study dynamic large deviations for the Kipnis--Marchioro--Presutti process on the discrete torus $\mathbb{T}_N^d$. By recasting the candidate rate function in terms of a linear hyperbolic-parabolic equation with rough drift, we show that pathological trajectories appear in the large deviations with finite rate in any dimension $d\ge 2$. Along the way, we rigorously validate the lower bound derived by Bertini-Gabrielli-Lebowitz in any dimension.