English

Small deviation estimates and small ball probabilities for geodesics in last passage percolation

Probability 2021-01-06 v1 Mathematical Physics math.MP

Abstract

For the exactly solvable model of exponential last passage percolation on Z2\mathbb{Z}^2, consider the geodesic Γn\Gamma_n joining (0,0)(0,0) and (n,n)(n,n) for large nn. It is well known that the transversal fluctuation of Γn\Gamma_n around the line x=yx=y is n2/3+o(1)n^{2/3+o(1)} with high probability. We obtain the exponent governing the decay of the small ball probability for Γn\Gamma_{n} and establish that for small δ\delta, the probability that Γn\Gamma_{n} is contained in a strip of width δn2/3\delta n^{2/3} around the diagonal is exp(Θ(δ3/2))\exp (-\Theta(\delta^{-3/2})) uniformly in high nn. We also obtain optimal small deviation estimates for the one point distribution of the geodesic showing that for t2n\frac{t}{2n} bounded away from 00 and 11, we have P(x(t)y(t)δn2/3)=Θ(δ)\mathbb{P}(|x(t)-y(t)|\leq \delta n^{2/3})=\Theta(\delta) uniformly in high nn, where (x(t),y(t))(x(t),y(t)) is the unique point where Γn\Gamma_{n} intersects the line x+y=tx+y=t. Our methods are expected to go through for other exactly solvable models of planar last passage percolation and, upon taking the nn\to \infty limit, provide analogous estimates for geodesics in the directed landscape.

Keywords

Cite

@article{arxiv.2101.01717,
  title  = {Small deviation estimates and small ball probabilities for geodesics in last passage percolation},
  author = {Riddhipratim Basu and Manan Bhatia},
  journal= {arXiv preprint arXiv:2101.01717},
  year   = {2021}
}

Comments

39 pages, 6 figures

R2 v1 2026-06-23T21:48:48.921Z