Asymptotic Properties of a Special Solution to the (3,4) String Equation

Abstract

We analyze the asymptotic properties a special solution of the $(3,4)$ string equation, which appears in the study of the multicritical quartic $2$-matrix model. In particular, we show that in a certain parameter regime, the corresponding $\tau$-function has an asymptotic expansion which is `topological' in nature. Consequently, we show that this solution to the string equation with a specific set of Stokes data exists, at least asymptotically. We also demonstrate that, along specific curves in the parameter space, this $\tau$-function degenerates to the $\tau$-function for a tritronqu\'{e}e solution of Painlev\'{e} I (which appears in the critical quartic $1$-matrix model), indicating that there is a `renormalization group flow' between these critical points. This confirms a conjecture from [1]. [1] The Ising model, the Yang-Lee edge singularity, and 2D quantum gravity, C. Crnkovi\'{c}, P. Ginsparg, G. Moore. Phys. Lett. B 237 2 (1990)