From stability to chaos in last-passage percolation

Daniel Ahlberg, Maria Deijfen, Matteo Sfragara

Published 2023-02-22Version 1

We study the transition from stability to chaos in a dynamic last passage percolation model on $\mathbb{Z}^d$ with random weights at the vertices. Given an initial weight configuration at time $0$, we perturb the model over time in such a way that the weight configuration at time $t$ is obtained by resampling each weight independently with probability $t$. On the square $[0,n]^2$, we study geodesics, that is, weight-maximizing up-right paths from $(0,0)$ to $(n,n)$, and their passage time $T$. Under mild conditions on the weight distribution, we prove a phase transition between stability and chaos at $t \asymp \frac{\mathrm{Var}(T)}{n}$. Indeed, as $n$ grows large, for small values of $t$, the passage times at time $0$ and time $t$ are highly correlated, while for large values of $t$, the geodesics become almost disjoint.