Aether for quantum gravity?! Dittrich says yes!
On the aether approach, we add the clocks to the system, by way of
– Gaussian reference fluids
– (honest) aether)
– dust proposals.
Huggett: Does the aether introduce some parameter? Dittrich: Aether is a bit more subtle, aether is just a vector field that is hypersurface-orthogonal and provides a slicing of the manifold.
Sudarski: does this break Lorentz-invariance? Dittrich seems willing to bite the bullett, although she describes this as a “diffeomorphism-invariant way” to break Lorentz invariance. This blogger, for one, is puzzled!
Beyond Spacetime 