A lower bound for point-to-point connection probabilities in critical percolation
Electronic Communications in Probability , Volume 25 p. 1- 9
Consider critical site percolation on Zd with d ≥ 2. We prove a lower bound of order n-d 2 for point-to-point connection probabilities, where n is the distance between the points. Most of the work in our proof concerns a ‘construction’ which finally reduces the problem to a topological one. This is then solved by applying a topological fact, Lemma 2.12 below, which follows from Brouwer’s fixed point theorem. Our bound improves the lower bound with exponent 2d(d-1), used by Cerf in 2015  to obtain an upper bound for the so-called two-arm probabilities. Apart from being of interest in itself, our result gives a small improvement of the bound on the two-arm exponent found by Cerf.
|Connection probabilities, Critical percolation|
|Electronic Communications in Probability|
van den Berg, J, & Don, H. (2020). A lower bound for point-to-point connection probabilities in critical percolation. Electronic Communications in Probability, 25, 1–9. doi:10.1214/20-ECP326