Higher genus meanders and Masur-Veech volumes

Abstract

A meander can be seen as a pair of transversally intersecting simple closed curves on a 2-sphere. We consider pairs of transversally intersecting simple closed curves on a closed oriented surface of arbitrary genus g. The number of such higher genus meanders admits exponential upper and lower bounds as the number of intersections grows. Fixing the number n of bigons in the complement to the union of the two curves, we compute the precise asymptotics of genus g meanders with at most 2N intersections and show that this asymptotics is polynomial in N as N tends to infinity. We obtain a similar result for the number of positively intersecting pairs of oriented simple closed curves on a surface of genus g. We also compute the asymptotic probability of getting a meander from a random braid on a surface of genus g-1 with two boundary components. In order to effectively count meanders we identify them with integer points represented by certain square-tiled surfaces in the moduli spaces of Abelian and quadratic differentials and make use of recent advances in the geometry of these moduli spaces combined with asymptotic properties of Witten-Kontsevich 2-correlators on moduli spaces of complex curves.