Canonical structure of Tetrad Bimetric Gravity

TL;DR

This paper provides a comprehensive canonical analysis of tetrad bimetric gravity, confirming its ghost-free nature and detailing the constraints that ensure the correct degrees of freedom for massless and massive gravitons.

Contribution

It offers explicit, covariant expressions for secondary constraints that eliminate ghosts and establish equivalence with metric formulations in tetrad bimetric gravity.

Findings

Confirmed ghost-free structure with seven degrees of freedom.

Derived simple, covariant secondary constraints.

Established equivalence with metric formulation.

Abstract

We perform the complete canonical analysis of the tetrad formulation of bimetric gravity and confirm that it is ghost-free describing the seven degrees of freedom of a massless and a massive gravitons. In particular, we find explicit expressions for secondary constraints, one of which is responsible for removing the ghost, whereas the other ensures the equivalence with the metric formulation. Both of them have a remarkably simple form and, being combined with conditions on Lagrange multipliers, can be written in a covariant way.