Orthogonal polynomials for the singularly perturbed Laguerre weight, Hankel determinants and asymptotics

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Hauptverfasser: Min, Chao, Wu, Xiaoqing
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Veröffentlicht: 2025
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author Min, Chao
Wu, Xiaoqing
author_facet Min, Chao
Wu, Xiaoqing
contents Based on the work of Chen and Its [{\em J. Approx. Theory} {\bf 162} ({2010}) {270--297}], we further study orthogonal polynomials with respect to the singularly perturbed Laguerre weight $w(x;t,α) = {x^α}{\mathrm e^{- x-\frac{t}{x}}}, \; x\in\mathbb{R}^{+},\;α> -1,\; t\geq 0$. By using the ladder operators and associated compatibility conditions for orthogonal polynomials with general Laguerre-type weights, we derive the second-order differential equation satisfied by the orthogonal polynomials, a system of difference equations and a system of differential-difference equations for the recurrence coefficients. We also investigate the properties of the zeros of the orthogonal polynomials. Using Dyson's Coulomb fluid approach together with the discrete system, we obtain the large $n$ asymptotic expansions of the recurrence coefficients, the sub-leading coefficient of the monic orthogonal polynomials, the Hankel determinant and the normalized constant for fixed $t>0$. It is found that all the asymptotic expansions are singular at $t=0$. We also study the long-time ($t\rightarrow+\infty$) asymptotics of these quantities explicitly for fixed $n\in\mathbb{N}$ from the Toda-type system.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09362
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Orthogonal polynomials for the singularly perturbed Laguerre weight, Hankel determinants and asymptotics
Min, Chao
Wu, Xiaoqing
Classical Analysis and ODEs
Mathematical Physics
42C05, 33C45, 41A60
Based on the work of Chen and Its [{\em J. Approx. Theory} {\bf 162} ({2010}) {270--297}], we further study orthogonal polynomials with respect to the singularly perturbed Laguerre weight $w(x;t,α) = {x^α}{\mathrm e^{- x-\frac{t}{x}}}, \; x\in\mathbb{R}^{+},\;α> -1,\; t\geq 0$. By using the ladder operators and associated compatibility conditions for orthogonal polynomials with general Laguerre-type weights, we derive the second-order differential equation satisfied by the orthogonal polynomials, a system of difference equations and a system of differential-difference equations for the recurrence coefficients. We also investigate the properties of the zeros of the orthogonal polynomials. Using Dyson's Coulomb fluid approach together with the discrete system, we obtain the large $n$ asymptotic expansions of the recurrence coefficients, the sub-leading coefficient of the monic orthogonal polynomials, the Hankel determinant and the normalized constant for fixed $t>0$. It is found that all the asymptotic expansions are singular at $t=0$. We also study the long-time ($t\rightarrow+\infty$) asymptotics of these quantities explicitly for fixed $n\in\mathbb{N}$ from the Toda-type system.
title Orthogonal polynomials for the singularly perturbed Laguerre weight, Hankel determinants and asymptotics
topic Classical Analysis and ODEs
Mathematical Physics
42C05, 33C45, 41A60
url https://arxiv.org/abs/2511.09362