On Matter Coupling in 5D Kaluza-Klein Model

TL;DR

This paper critiques the traditional geodesic approach in 5D Kaluza-Klein models, identifies its issues, and introduces a new Papapetrou multipole expansion method that resolves these problems.

Contribution

It proposes a novel multipole expansion approach for matter coupling in 5D Kaluza-Klein models, avoiding unphysical features of previous methods.

Findings

Eliminates the q/m puzzle

Prevents the emergence of huge massive modes

Provides correct matter couplings in 5D models

Abstract

We analyze some unphysical features of the geodesic approach to matter coupling in a compactified Kaluza-Klein scenario, like the q/m puzzle and the huge massive modes. We propose a new approach, based on Papapetrou multipole expansion, that provides a new equation for the motion of a test particle. We show how this equation provides right couplings and does not generate huge massive modes.