The higher spin Laplace operator

TL;DR

This paper introduces higher spin conformally invariant second-order differential operators extending the Laplace operator, constructed via Clifford analysis, and investigates their properties including ellipticity, kernel, and fundamental solutions.

Contribution

It develops a new class of higher spin Laplace operators within Clifford analysis, generalizing classical operators and analyzing their fundamental properties.

Findings

Operators are elliptic.

Kernel characterized for polynomial solutions.

Fundamental solutions constructed.

Abstract

This paper deals with a certain class of second-order conformally invariant operators acting on functions taking values in particular (finite-dimensional) irreducible representations of the orthogonal group. These operators can be seen as a generalisation of the Laplace operator to higher spin as well as a second order analogue of the Rarita-Schwinger operator. To construct these operators, we will use the framework of Clifford analysis, a multivariate function theory in which arbitrary irreducible representations for the orthogonal group can be realised in terms of polynomials satisfying a system of differential equations. As a consequence, the functions on which this particular class of operators act are functions taking values in the space of harmonics homogeneous of degree k. We prove the ellipticity of these operators and use this to investigate their kernel, focusing on both polynomial solutions and the fundamental solution.