Celestial meets de Sitter holography

Session

Topical Seminars

16 Jun 2025, 14:00

Villa Orlandi, Capri

1. Celestial CFT data: w-(1+infty) and beyond

Andrea Puhm

16/06/2025, 14:00

2. High-energy string theory and celestial holography

Stephan Stieberger

16/06/2025, 14:30

In my talk I make connection between two seemingly unrelated topics: (a) the high energy limit of string theory (more specifically, the high energy (zero tension) limit of tree-level string scattering in flat backgrounds) and its subleading corrections as saddle-point approximation on the string world-sheet, (b) the infinite energy limit of celestial string amplitudes as stationary phase...

3. Soft Algebras in AdS4 and dS4

Andrew Strominger

16/06/2025, 15:30

4. Carrollian Amplitudes and Holographic Correlators in AdS3/CFT2

Bin Zhu

16/06/2025, 16:00

With the new notions of flat holography introduced in recent years, there has been increased interest in relating the new formalisms to the flat space limit of AdS/CFT. We study Carrollian amplitudes of massless scalars in (1+2) Minkowski space. Using the prescription recently shown by Alday et al. [1] originally designed for the AdS4 Witten diagrams, we show that AdS3 Witten diagrams in...

6. Hartle-Hawking revisited

Jordan Cotler

17/06/2025, 14:00

By leveraging recent insights on de Sitter holography from low-dimensional gravity, we study basic properties of the quantum mechanics of the Hartle-Hawking wavefunction in general dimensions. We highlight connections to basic puzzles in de Sitter quantum gravity.

5. Finite boundaries meet all-Lambda’s holography

Damián Galante

17/06/2025, 14:30

I will describe recent progress in trying to understand the theory of general relativity in manifolds with finite boundaries and comment on possible holographic applications, in principle valid for any value of the cosmological constant.

8. Insights from exact results in dS

Alan Rios Fukelman

17/06/2025, 15:30

In this talk I will present an exactly solvable theory on a fixed de Sitter spacetime that can be analyzed efficiently using Euclidean methods. I will then discuss the fully non-perturbative, all loop correlation function of gauge invariant operators and demonstrate many features endemic of quantum field theory in de Sitter space such as the appearance of late-time logarithm and their...

7. TBA

Tarek Anous

17/06/2025, 16:00

13. Infrared structure of gravitational scattering up to quadrupolar order

Geoffrey Compère

19/06/2025, 14:00

Asymptotically flat spacetimes have been defined from consistently matching their five infinities such that they share a single BMS group of asymptotic symmetries and associated charges. We propose a consistent subleading and subsubleading structure which is covariant under the BMS group. At subleading order, we identify three conservation laws: tails are conserved between past and future null...

14. (Anti-) de Sitter deformations of celestial symmetries and their twistor origin

Lionel Mason

19/06/2025, 14:30

This talk will review the twistor origins of celestial symmetry algebras and their deformations/extension to (A)dS. It will go on to discuss their origin as Hamiltonians via twistor actions and connections with the integral systems literature and top down approaches to celestial holography. This is partly based on joint work with Bittleston, Bogna, Kmec & Skinner arxiv:2403.18011 and with...

15. On the mixed helicity sector of celestial symmetries

Daniele Pranzetti

19/06/2025, 15:30

The mixed helicity sector of celestial symmetries has been largely unexplored so far. I will report on recent progress in expressing the mixed helicity charge bracket for gravity and YM theory in a closed form, revealing the key role played by the shadow transformation. The correspondence between the hard charge action on conformal primary fields and the celestial OPE provides consistency...

16. TBA

David Skinner

19/06/2025, 16:00

9. A geometrical picture for processes in expanding universes

Paolo Benincasa

20/06/2025, 14:00

I present a first principle definition of the Bunch-Davies
wavefunctional in perturbation theory for generic scalars in arbitrary
FRW cosmologies. This novel picture generalises the original
description of conformally-coupled and light states in terms of
(generalised) cosmological polytopes. I'll comment on the insights that
it provides on the analytic structure of such an observables,...

10. TBA

Austin Joyce

20/06/2025, 14:30

11. A few basic facts about de Sitter and Anti-de Sitter quantum field theory and some of their applications

Ugo Moschella

20/06/2025, 15:30

A will discuss a general covariant approach to dS and AdS QFT based on plane waves and the global analyticity properties of the correlation functions. I will also sketch some recent results including the exact calculation of one and two-loop diagrams

12. Twistors and Spin in cosmology

Guilherme Pimentel

20/06/2025, 16:00

I will describe how twistors are the natural language to describe massless particles with spin in de Sitter space, and illustrate the formalism with some examples.