Asymptotics of the instantons of Painleve I
Stavros Garoufalidis, Alexander Its, Andrei Kapaev, Marcos Marino
TL;DR
This work advances the understanding of Painlevé I non-perturbative structure by deriving all-orders asymptotics for the 0- and 1-instantons via Riemann-Hilbert analysis and formulating resurgent trans-series predictions for fixed-k instantons. It reveals a refined resurgence framework linking $u_{n,k}$ to neighboring instanton data through explicit algebraic recursions, Stokes constants, and logarithmic corrections, including an induced Stokes phenomenon arising from tritronquée solutions. The results are substantiated with numerical evidence, illustrating the accuracy of the asymptotic expansions and the presence of new phenomena for $krakge2$, with implications for non-perturbative effects in matrix models and non-critical string theory.
Abstract
The 0-instanton solution of Painlevé I is a sequence $(u_{n,0})$ of complex numbers which appears universally in many enumerative problems in algebraic geometry, graph theory, matrix models and 2-dimensional quantum gravity. The asymptotics of the 0-instanton $(u_{n,0})$ for large $n$ were obtained by the third author using the Riemann-Hilbert approach. For $k=0,1,2,...$, the $k$-instanton solution of Painlevé I is a doubly-indexed sequence $(u_{n,k})$ of complex numbers that satisfies an explicit quadratic non-linear recursion relation. The goal of the paper is three-fold: (a) to compute the asymptotics of the 1-instanton sequence $(u_{n,1})$ to all orders in $1/n$ by using the Riemann-Hilbert method, (b) to present formulas for the asymptotics of $(u_{n,k})$ for fixed $k$ and to all orders in $1/n$ using resurgent analysis, and (c) to confirm numerically the predictions of resurgent analysis. We point out that the instanton solutions display a new type of Stokes behavior, induced from the tritronquée Painlevé transcendents, and which we call the induced Stokes phenomenon. The asymptotics of the 2-instanton and beyond exhibits new phenomena not seen in 0 and 1-instantons, and their enumerative context is at present unknown.
