A canonical bracket for open gravitational system

Understand

This paper shows that the generalization of the Barnich-Troessaert bracket recently proposed to represent the extended corner algebra can be obtained as the canonical bracket for an extended gravitational Lagrangian.

• This extension effectively allows one to reabsorb the symplectic flux into the dressing of the Lagrangian by an embedding field.
• It also implies that the canonical Poisson bracket of charges forms a representation of the extended corner symmetry algebra.