Geometric multipliers and partial teleparallelism in Poincar\'e gauge theory

TL;DR

This paper explores how geometric multipliers in Poincaré gauge theory can control curvature and torsion components, potentially stabilizing strong-field regimes and avoiding unwanted dynamics like ghosts.

Contribution

It generalizes the use of multipliers to disable specific curvature or torsion parts in Poincaré gauge theory, offering a new approach to manage strong-field behavior.

Findings

Geometric multipliers can disable any irreducible curvature or torsion component.

They may limit strong-field deviations from weak-field constraints.

Potential to prevent ghost-like instabilities in torsion theories.

Abstract

The dynamics of the torsion-powered teleparallel theory are only viable because thirty-six multiplier fields disable all components of the Riemann--Cartan curvature. We generalise this suggestive approach by considering Poincar\'e gauge theory in which sixty such `geometric multipliers' can be invoked to disable any given irreducible part of the curvature, or indeed the torsion. Torsion theories motivated by a weak-field analysis frequently suffer from unwanted dynamics in the strong-field regime, such as the activation of ghosts. By considering the propagation of massive, parity-even vector torsion, we explore how geometric multipliers may be able to limit strong-field departures from the weak-field Hamiltonian constraint structure, and consider their tree-level phenomena.