Explicit Formulas for the One-Parameter Group Generated by the Dunkl Operator on $\mathbb{R}$

TL;DR

This paper explicitly computes the unitary one-parameter group generated by a Dunkl operator on the real line, providing boundary value and real-variable integral representations involving Legendre functions.

Contribution

It derives explicit formulas for the one-parameter group generated by the Dunkl operator, including novel boundary value and integral representations.

Findings

Explicit formulas for the unitary group $e^{tD_b}$ are obtained.

Two representations are provided: boundary value and real-variable integral.

The kernel involves Legendre functions, enabling further analysis.

Abstract

Let $T_{b}$ be the Dunkl operator for the reflection group $G=\mathbb{Z}/2\mathbb{Z}$, and $D_{b}:=|x|^{b}\,T_{b}\,|x|^{-b}$. We compute explicitly the unitary one-parameter group $e^{tD_{b}}$ generated by $D_{b}$. We obtain two representations: a boundary value representation from the upper and lower half-planes, and a real-variable formula consisting of a translation term and a principal value integral term with an explicit kernel expressed in terms of Legendre functions.