Working in the self-dual sector for Yang-Mills and gravity, we show how to construct an extended phase space at null infinity, to all orders in the radial expansion. This formalises the symmetry origin of the infrared behaviour of these theories to all subleading orders. As a corollary, we also derive a double copy mapping from a subset of YM gauge transformations to a subset of diffeomorphisms to all orders in the transformation parameters, which to our knowledge has not been presented before in the literature.
Nagy, S., & Peraza, J. (2023). Radiative phase space extensions at all orders in r for self-dual Yang-Mills and gravity. Journal of High Energy Physics, 2023(2), Article 202. https://doi.org/10.1007/jhep02%282023%29202