Fields on the Poincare group: arbitrary spin description and relativistic wave equations

TL;DR

This paper develops a group-theoretical framework for describing particles with arbitrary spins using scalar fields on the Poincare group, leading to new relativistic wave equations for various spins and dimensions.

Contribution

It introduces a unified approach to derive finite- and infinite-component wave equations from scalar fields on the Poincare group, encompassing different spins and dimensions.

Findings

Derived relativistic wave equations for particles with specific spins and masses.

Classified scalar functions leading to finite- and infinite-component wave equations.

Established automorphisms for discrete symmetries C, P, T within the group-theoretical framework.

Abstract

In this paper, starting from pure group-theoretical point of view, we develop a regular approach to describing particles with different spins in the framework of a theory of scalar fields on the Poincare group. Such fields can be considered as generating functions for conventional spin-tensor fields. The cases of 2, 3, and 4 dimensions are elaborated in detail. Discrete transformations $C,P,T$ are defined for the scalar fields as automorphisms of the Poincare group. Doing a classification of the scalar functions, we obtain relativistic wave equations for particles with definite spin and mass. There exist two different types of scalar functions (which describe the same mass and spin), one related to a finite-dimensional nonunitary representation and another one related to an infinite-dimensional unitary representation of the Lorentz subgroup. This allows us to derive both usual finite-component wave equations for spin-tensor fields and positive energy infinite-component wave equations.