Events

Date: 19 March 2026   Time: 14:00 - 15:00

Location: Room 610, G.O. Jones Building

Gravitational charges and radiation in de Sitter

I will present a first principles rigorous derivation of gravitational charges in de Sitter using (suitably adapted version of) Noether's theorem, and show that they satisfy a flux-balance law. The variational problem in de Sitter gravity requires that one specifies a conformal class up to diffeomorpshisms at future and past infinity. Gravitational radiation is possible only when the conformal class is non-trivial. I will illustrate the discussion with several exact solutions, including the radiative Robinson-Trautman-dS solution, which I will use to demonstrate the existence of conserved charges even in the absence of asymptotic (conformal) Killing vectors, and also the existence of monotonic charges, charges that are not conserved but rather change monotonically under time evolution. An example of a monotonic change is the Bondi mass.