The true radiation gauge for gravity

الأصل · EN

Corresponding to the similarity between the Lorentz gauge ∂μAμ=0 in electrodynamics and gμνΓρμν=0 in gravity, we show that the counterpart of the radiation gauge ∂ᵢAⁱ=0 is gijΓρij=0, in stead of other forms as discussed before. Particularly: 1) at least for a weak field, gijΓρij=0 fixes the gauge completely and picks out exactly the two physical components of the gravitational field; 2) like A⁰, the non-dynamical components h₀μ are solved instantaneously; 3) gravitational radiation is generated by the "transverse" part of the energy-momentum tensor, similar to the transverse current J⊥. This true" radiation gauge gijΓρij=0 is especially pertinent for studying gravitational energy, such as the energy flow in gravitational radiation. It agrees with the transverse-traceless (TT) gauge for a pure wave, and reveals remarkably how the TT gauge can be adapted in the presence of source.