General Covariant Gauge Fixing for Massless Spin-Two Fields

Understand

The most general covariant gauge fixing Lagrangian is considered for a spin-two gauge theory in the context of the Faddeev-Popov procedure.

• In general, five parameters characterize this gauge fixing.
• Certain limiting values for these parameters give rise to a spin-two propagator that is either traceless or transverse, but for no values of these parameters is this propagator simultaneously traceless and transverse.
• Having a traceless-transverse (TT) propagator ensures that only the physical degrees of freedom associated with the tensor field propagate, and hence it is analogous to the Landau gauge in electrodynamics.