Chiral massive news: null boundary symmetries in topologically massive gravity

We study surface charges on a generic null boundary in three dimensional topological massive gravity (TMG). We construct the solution phase space which involves four independent functions over the two dimensional null boundary. One of these functions corresponds to the massive chiral propagating graviton mode of TMG. The other three correspond to three surface charges of the theory, two of which can always be made integrable, while the last one can become integrable only in the absence of the chiral massive graviton flux through the null boundary. As the null boundary symmetry algebra we obtain Heisenberg circle plus Virasoro algebra with a central charge proportional to the gravitational Chern-Simons term of TMG. We also discuss that the flux of the chiral massive gravitons appears as the (Bondi) news through the null surface.

Automated summary

The study focuses on surface charges on a generic null boundary in three dimensional topological massive gravity, constructing the solution phase space with four independent functions. One function corresponds to the chiral propagating graviton mode, while the other three correspond to distinct surface charges of the theory. The null boundary symmetry algebra is identified as Heisenberg circle plus Virasoro algebra, with a central charge related to the gravitational Chern-Simons term of TMG.