Null Raychaudhuri: Canonical Structure and the Dressing Time

Understand

We initiate a study of gravity focusing on generic null hypersurfaces, non-perturbatively in the Newton coupling.

• We present an off-shell account of the extended phase space of the theory, which includes the expected spin-2 data as well as spin-0, spin-1 and arbitrary matter degrees of freedom.
• We construct the charges and the corresponding kinematic Poisson brackets, employing a Beltrami parameterization of the spin-2 modes.
• We explicitly show that the constraint algebra closes, the details of which depend on the non-perturbative mixing between spin-0 and spin-2 modes.