Key points are not available for this paper at this time.
A bstract We construct the boundary phase space in D -dimensional Einstein gravity with a generic given co-dimension one null surface N N as the boundary. The associated boundary symmetry algebra is a semi-direct sum of diffeomorphisms of N N and Weyl rescalings. It is generated by D towers of surface charges that are generic functions over N N. These surface charges can be rendered integrable for appropriate slicings of the phase space, provided there is no graviton flux through N N. In one particular slicing of this type, the charge algebra is the direct sum of the Heisenberg algebra and diffeomorphisms of the transverse space, N N v for any fixed value of the advanced time v. Finally, we introduce null surface expansion- and spin-memories, and discuss associated memory effects that encode the passage of gravitational waves through N N, imprinted in a change of the surface charges.
Adami et al. (Mon,) studied this question.