English

Near-existence of bigeodesics in dynamical exponential last passage percolation

Probability 2025-11-03 v2

Abstract

It is believed that, under very general conditions, bi-infinite geodesics (or bigeodesics) do not exist for planar first and last passage percolation (LPP) models. However, if one endows the model with a natural dynamics, thereby gradually perturbing the geometry, then it is plausible that there could exist a non-trivial set T\mathscr{T} of exceptional times at which such bigeodesics exist. For dynamical exponential LPP, we show that T\mathscr{T} is "very close" to being non-trivial; namely, we obtain an Ω(1/logn)\Omega( 1/\log n) lower bound on the probability that there exists a random time t[0,1]t\in [0,1] at which a non-trivial geodesic of length nn passes through the origin at its midpoint; note that if the above probability were Ω(1)\Omega(1), then it would imply the non-triviality of T\mathscr{T}. We conjecture that, even if T\mathscr{T}\neq \emptyset, it a.s. has Hausdorff dimension exactly zero.

Keywords

Cite

@article{arxiv.2504.12293,
  title  = {Near-existence of bigeodesics in dynamical exponential last passage percolation},
  author = {Manan Bhatia},
  journal= {arXiv preprint arXiv:2504.12293},
  year   = {2025}
}

Comments

29 pages, 6 figures. The two main results of the previous version concerned entirely different models and relied on distinct proof techniques. Accordingly, the material has now been reorganized into two separate papers. The present version is one of these, and a companion article "Geodesic switches and exceptional times in dynamical Brownian last passage percolation" has been posted separately