Hamiltonian Dynamics for Proca's theories in five dimensions with a compact dimension

TL;DR

This paper analyzes the Hamiltonian structure of Proca's theory in five dimensions with a compact dimension, revealing it describes massive vector and scalar fields without gauge symmetry, and extends to a BF-like theory.

Contribution

It provides a detailed canonical analysis of Proca's theory in five dimensions with compactification, including degrees of freedom and constraint structure, and explores a BF-like extension.

Findings

The theory lacks first class constraints and gauge symmetry.

The four-dimensional effective theory includes massive vector, scalar, and KK modes.

The BF-like extension is not topological and has reducibility conditions.

Abstract

The canonical analysis of Proca's theory in five dimensions with a compact dimension is performed. From the Proca five dimensional action, we perform the compactification process on a S^1/\mathbf{Z_2} orbifold, then, we analyze the four dimensional effective action that emerges from the compactification process. We report the extended action, the extended Hamiltonian and the counting of degrees of freedom of the theory. We show that the theory with the compact dimension continues laking of first class constraints. In fact, the final theory is not a gauge theory and describes the propagation of a massive vector field plus a tower of massive KK-excitations and one massive scalar field. Finally, we perform the analysis of a 5D BF-like theory plus a Proca's term, we perform the compactification process and we find all constraints of the theory, we also carry out the counting of physical degrees of freedom; with these results, we conclude that the theory is not topological and has reducibility conditions among the constraints.