From Asymtptotic Symmetries to Flat Holography: Theoretical Aspects and Observable Consequences

Gravity and gauge theories share a rich infrared physics whose universal features manifest themselves in the context of asymptotic symmetries and their Noether charges. They clarify the soft factorization properties of scattering amplitudes, they play a role in the phenomenology of gravitational waves, and enter in the identification of new observable effects including gravitational and color memories. From the perspective of quantum gravity, they introduce new tools to understand the structure of the Hilbert space, and bring about a novel and promising approach to investigate a holographic principle for asymptotically flat spacetimes, currently pursued along two related lines: celestial and Carrollian holography. The latter exploits the Carroll structure at null infinity while the former takes advantage of powerful toolkit of conformal field theory. The vast majority of these developments have taken place in the last ten years and gave rise to research lines currently undergoing a fast growth. The proposed workshop aims at exploiting this rich and timely topic to bring together experts from all over the world, together with young researchers and students, with the goal to provide training, share results, build common grounds and foster new collaborations.

Topics: Asymptotic symmetries; Celestial holography; Carroll physics and geometry; Twistor methods; Gravitational observables; Memory effects; Conformal colliders