Twistor action for full Einstein gravity
Develop and establish the status of a twistor action for full Einstein gravity suitable for extending the charge construction beyond the self-dual sector.
References
Unlike the Yang-Mills case, the status of the twistor action for full Einstein gravity is not clear, although see for a route into the subject that restricts the twistor action for full conformal gravity to Einstein modes.
Another important question concerns the Ward identities associated with these charges. Their conservation and interpretation as symmetry generators suggest an infinite family of Ward identities extending the usual conformal Ward identities. It would be important to establish their precise form and to determine whether they persist beyond the linearised or self-dual sectors.