Unconstrained canonical action for, and positive energy of, massive spin 2

TL;DR

This paper presents a positive-energy formulation of the massive spin-2 field in four dimensions, using an unconstrained helicity decomposition to address the helicity-0 sector issues.

Contribution

It introduces a new unconstrained canonical action for the massive spin-2 field with positive energy, filling a key gap in the theoretical understanding.

Findings

Explicit unconstrained helicity decomposition of the massive spin-2 field.

Demonstration of manifestly positive energy for the action.

Resolution of the helicity-0 sector problem.

Abstract

Filling a much-needed gap, we exhibit the D=4 Fierz-Pauli (FP) massive s=2 action, and its--manifestly positive--energy, in terms of its 2s+1=5 unconstrained helicity (2,1,0) excitations, after reducing and diagonalizing the troublesome helicity-0 sector.