The gauge structure of strong coupling gravity

This is the authors' abstract. We don't add key points for this paper.

In the limit of infinite Newton constant the dimensional Einstein–Hilbert action reduces to that of a nonlinear sigma-model where spatial points are coupled merely by shift terms giving rise to a diffeomorphism constraint. The full group of diffeomorphisms is shown to act non-tensorially as a gauge group on the action and the field equations. This is used to establish the admissibility as a gauge condition of the combined constant mean curvature (CMC) and zero shift conditions for spatially closed hypersurfaces. This 'CMC gauge' eventually allows for a concise isolation of the gauge invariant and physical degrees of freedoms. Here we utilize the CMC gauge to obtain a complete set of dynamical fields which are invariant under all gauge transformations but time independent spatial diffeomorphisms.