Painlev\'e III asymptotics of Hankel determinants for a perturbed Jacobi weight

TL;DR

This paper derives asymptotic formulas for Hankel determinants associated with a perturbed Jacobi weight near a critical point, using Painlevé III equations and steepest descent analysis.

Contribution

It provides the first detailed asymptotic analysis of Hankel determinants with a perturbed Jacobi weight in a double scaling limit, connecting to Painlevé III functions.

Findings

Asymptotic formulas for Hankel determinants near critical point

Explicit expressions involving Painlevé III $ au$-function

Results for leading and recurrence coefficients of perturbed Jacobi polynomials

Abstract

We study the Hankel determinants associated with the weight $$w(x;t)=(1-x^2)^{\beta}(t^2-x^2)^\alpha h(x),~x\in(-1,1),$$ where $\beta>-1$, $\alpha+\beta>-1$, $t>1$, $h(x)$ is analytic in a domain containing $[-1,1]$ and $h(x)>0$ for $x\in[-1,1]$. In this paper, based on the Deift-Zhou nonlinear steepest descent analysis, we study the double scaling limit of the Hankel determinants as $n\to \infty$ and $t\to 1$. We obtain the asymptotic approximations of the Hankel determinants, evaluated in terms of the Jimbo-Miwa-Okamoto $\sigma$-function for the Painlev\'{e} III equation. The asymptotics of the leading coefficients and the recurrence coefficients for the perturbed Jacobi polynomials are also obtained.