Celestial Lw(1+infinity) Symmetries of Gravity from a Twistor Space Action
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Bat. Braconnier
It has long been known that the symmetries of gravity in asymptotically flat spacetimes form the BMS algebra, which plays a crucial role in infrared physics. Recently, a new infinite tower of symmetries enhancing the BMS algebra—forming the \text{Lw}(1+\infty)Lw(1+infinity) algebra—has been uncovered in the context of celestial holography by analyzing the collinear limit of scattering amplitudes. In this talk, I will explain how these symmetries naturally emerge from twistor space, a three-complex-dimensional space related to spacetime via a non-local Penrose transform. I will derive the charges associated with these symmetries from a twistor space action using standard Hamiltonian methods. Finally, I will provide explicit expressions for these charges in spacetime and discuss their relevance for gravitational physics.
Johannes Kellendonk, Alexander Thomas