Double copy and the double Poisson bracket
Joon-Hwi Kim
TL;DR
This work presents a unified ambitwistor-space framework in which YM theory and general relativity emerge from gauge-covariant constrained quantization of massless particle phase spaces. By incorporating covariantized, star-product–based OPEs on ambitwistor worldlines and one-loop diagrams, the authors derive both first-order (magnetic/electric) and second-order (Penrose-type) field equations, suggesting a covariant double Poisson bracket structure $\{\{H,H\}\}_{\nabla}=0$. A central theme is the Fedosov construction of gauge-covariant associative algebras, which reconciles covariance with associativity and underpins a potential ambitwistor-based realization of BCJ duality through BAS-type equations. The framework extends to $\mathcal{N}=1$ and $\mathcal{N}=2$ ambitwistor particles for YM and GR, respectively, and culminates in a covariant BAS formulation of gravity, including teleparallel/Born-Infeld viewpoints. Overall, the paper proposes that the kinematic (double copy) algebra may be realized as the Poisson/double Poisson structure of ambitwistor space in general dimensions, offering a new route to understanding gauge–gravity relations beyond self-duality limits.
Abstract
We derive first-order and second-order field equations from ambitwistor spaces as phase spaces of massless particles. In particular, the second-order field equations of Yang-Mills theory and general relativity are formulated in a unified form $\{\{H,H\}\}_\nabla = 0$, whose left-hand side describes a doubling of Poisson bracket in a covariant sense. This structure originates from a one-loop diagram encoded in gauge-covariant, associative operator products on the ambitwistor worldlines. A conjecture arises that the kinematic algebra might manifest as the Poisson algebra of ambitwistor space.
