# Higher order superintegrability, Painlev\'e transcendents and representations of polynomial algebras

## TL;DR

This paper advances the classification of higher order superintegrable systems, explores their algebraic structures, and links nonlinear differential equations with Painlevé properties to their solvability and spectral characteristics.

## Contribution

It introduces new algebraic techniques for classifying superintegrable systems and proposes conjectures connecting Painlevé equations to their solvability.

## Key findings

- Complete classification of exotic potentials with third, fourth, and fifth order integrals.
- Identification of polynomial algebras generated by superintegrable systems.
- Alternative integrals enable algebraic solutions when standard methods fail.

## Abstract

In recent years, progress toward the classification of superintegrable systems with higher order integrals of motion has been made. In particular, a complete classification of all exotic potentials with a third or a fourth order integrals, and allowing separation of variables in Cartesian coordinates. All doubly exotic potentials with a fifth order integral have also been completely classified. It has been demonstrated how the Chazy class of third order differential equations plays an important role in solving determining equations. Moreover, taking advantage of various operator algebras defined as Abelian, Heisenberg, Conformal and Ladder case of operator algebras, we re-derived these models. These new techniques also provided further examples of superintegrable Hamiltonian with integrals of arbitrary order. It has been conjectured that all quantum superintegrable potentials that do not satisfy any linear equation satisfy nonlinear equations having the Painlev\'e property. In addition, it has been discovered that their integrals naturally generate finitely generated polynomial algebras and the representations can be exploited to calculate the energy spectrum. For certain very interesting cases associated with exceptional orthogonal polynomials, these algebraic structures do not allow to calculate the full spectrum and degeneracies. It has been demonstrated that alternative sets of integrals which can be build and used to provide a complete solution. This this allow to make another conjecture i.e. that higher order superintegrable systems can be solved algebraically, they require alternative set of integrals than the one provided by a direct approach.