The upcoming talk
At the next session of the TCS,
on the 12th of November 2025,
at 2:15 – 4:15 p.m. CET / 3:15 – 5:15 p.m. EET
Marcin Piątek
(Instytut Fizyki, Uniwersytet Szczeciński)
shall talk about
“Geometric Foundations of Celestial Amplitudes“.
Abstract
The geometric foundations of celestial holography will be developed, providing a reformulation of scattering theory in asymptotically flat spacetimes in which momentum-space amplitudes will be reorganized as conformal correlators on the celestial sphere at null infinity. The conventional framework will be reviewed through Penrose’s conformal compactification of Minkowski space, the analysis of the structure of future and past null infinity I±, and the identification of the celestial sphere S2 as the natural geometric setting for boundary data. The Mellin transform will be introduced to trade energy variables for conformal dimensions, leading to the construction of conformal primary wavefunctions from bulk plane waves and to the interpretation of soft theorems as Ward identities of a celestial conformal field theory on S2. In the second part, a differential-geometric formulation will be proposed, in which scattering amplitudes will be realized as distributional sections over null infinity and Mellin maps will be interpreted as fiberwise pushforwards. Potential implications and future directions of this geometric program on celestial amplitudes will be outlined.
(All seminar talks are given on the online zoom platform. Unless requested otherwise by the speaker or required by the circumstances, and then specifically indicated in the announcement, the talks consist of two halves, 45 minutes each, separated by a 15-minute break. The web link for every session is circulated via the TCS mailing list. In order to be enlisted, please contact the Organisers.)
Calendar 2025/2026
| Date | Speaker (affiliation) | Title (with a link to the slides, whenever available) |
| October 15th, 2025 | Athanasios Chatzistavrakidis (Ruđer Bošković Institute, Zagreb) | Basic curvature tensors in geometry and physics |
| October 29th, 2025 | Martha Valentina Guarín Escudero (Charles University, Faculty of Mathematics and Physics, Prague) | Fedosov connections and L∞-algebras associated to dg-manifolds |
| November 12th, 2025 | Marcin Piątek (Instytut Fizyki, Uniwersytet Szczeciński) | Geometric Foundations of Celestial Amplitudes |
| November 3rd, 2025 | Jakub R. Filipek (WFUW, Warszawa) | TBA |
| December 17th, 2025 | Rafał R. Suszek (KMMF, WFUW) | Stacky Dynamics in the Shadows of Principaloid Bundles |
| January 14th, 2026 | Richard J. Szabo (School of Mathematical and Computer Sciences, Heriot-Watt University, Edinburgh) | TBA |
| January 28th, 2026 | Cristian Ortiz (IME-USP, São Paulo) | TBA |
| February 25th, 2026 | Mikołaj Korzyński (CFT PAN) | TBA |
| March 11th, 2026 | ||
| March 25th, 2026 | ||
| April 8th, 2026 | ||
| April 22nd, 2026 | ||
| May 6th, 2026 | ||
| May 20th, 2026 | ||
| June 3rd, 2026 | ||