Connection between quantum systems involving the fourth Painleve transcendent and $k$-step rational extensions of the harmonic oscillator related to Hermite EOP

TL;DR

This paper reveals a connection between a quantum Hamiltonian involving the fourth Painleve transcendent and k-step rational extensions of the harmonic oscillator, linking special functions, supersymmetric quantum mechanics, and exceptional orthogonal polynomials.

Contribution

It establishes an explicit equivalence between Painleve-based Hamiltonians and k-step rational extensions using rational solutions and ladder operators, advancing understanding of exactly solvable quantum models.

Findings

Established the Hamiltonian equivalence using Painleve solutions and generalized Hermite polynomials.

Related ladder operators from supersymmetric constructions to the spectrum of the models.

Clarified the connection between Painleve transcendents and exceptional orthogonal polynomials.

Abstract

The purpose of this communication is to point out the connection between a 1D quantum Hamiltonian involving the fourth Painleve transcendent P$_{\rm IV}$, obtained in the context of second-order supersymmetric quantum mechanics and third-order ladder operators, with a hierarchy of families of quantum systems called $k$-step rational extensions of the harmonic oscillator and related with multi-indexed $X_{m_{1},m_{2},...,m_{k}}$ Hermite exceptionnal orthogonal polynomials of type III. The connection between these exactly solvable models is established at the level of the equivalence of the Hamiltonians using rational solutions of the fourth Painleve equation in terms of generalized Hermite and Okamoto polynomials. We also relate the different ladder operators obtained by various combinations of supersymmetric constructions involving Darboux-Crum and Krein-Adler supercharges, their zero modes and the corresponding energies. These results will demonstrate and clarify the relation observed for a particular case in previous papers.