Observables in gauge theory and gravity

10 déc. 2025, 08:00 → 12 déc. 2025, 18:45 Europe/Paris

Salle Itzykson (Institut de Physique Théorique, CEA-Saclay)

Didina Serban (Institut de Physique Theorique Saclay), Dmitry Chicherin (LAPTh, CNRS), Gregory Korchemsky (Institut de Physique Théorique - CEA/Saclay), Pierre Vanhove (IPhT CEA-Saclay)

 

 

 

This workshop will gather scientists working on observables in classical gravity and gauge theories.  

The three main topics that will be covered are :

•  Classical Gravitational Observables
•  Energy Correlations
•  Integrability of correlation functions and amplitudes

 

Invited Speakers

• Benjamin Basso (LPENS)
• Dimitry Chicherin (LAPTh)
• Leonardo de la Cruz (IPhT)
• Lance Dixon (SLAC)
• Veronica Fantini (Université Paris-Saclay)
• Gwenael Ferrando (Bonn)
• Carlo Heissenberg (IPhT)
• Eric Perlmutter (IPhT)
• Victor Mishnyakov (Nordita)
• Julio Parra-Martinez (IHES)
• Prashanth Raman (MMPI)
• Leonid Shumilov (University of Hamburg)
• Alessandro Testa (IPhT)
• Filippo Vernizzi (IPhT)
• Alexander Zhiboedov (CERN)

The talks are by invitation only

 

Organising Committee: Dimitry Chicherin, Gregory Korchemsky, Didina Serban, Pierre Vanhove.
Support: ANR Observable,IPhT, IRN:QFS

Editor uploads illustration_workshop.png

mer. 10 décembre

1 Black holes, naturalness and the renormalization group

test

Orateur: Julio Parra-Martinez (IHES)

2 Worldlines in a plasma

Orateur: Leonardo de la Cruz (IPhT CEA-Saclay)

plasma-wordline.pdf

11:00 Coffee and Free Discussions

3 Nonlinear gravitational memory from scattering amplitudes

Orateur: Carlo Heissenberg

12:45 Dejeuner

4 L-functions and Randomness in 2d CFTs

Orateur: Eric Perlmutter (IPhT CEA-Saclay)

15:30 Coffee and Free discussions

5 Static Quadratic Love Numbers

Orateur: Filippo Vernizzi (IPhT - CEA Saclay)

17:00 Free Discussions

jeu. 11 décembre

6 Conformal collider bootstrap

Orateur: Alexander Zhiboedov (CERN)

7 Resuming perturbative invariants of hyperbolic knots

Given a hyperbolic knot, the Andersen-Kashaev state integrals are convergent integrals associated with certain triangulations of the knot complement. Their asymptotic expansion is a perturbative topological invariant conjectured to be resurgent and Borel summable by Garoufalidis, Gu, and Mariño.
Motivated by resuming these perturbative invariants, we define a new homology theory that allows us to construct exponential period integrals, whose asymptotic expansion recovers the original divergent series.
In this talk, I will explain the main ideas of our construction, and time permitting, how they can be generalized to study similar classes of exponential period integrals (e.g. Feynman integrals in the Baikov representation).

Based on a joint project with C. Wheeler (arXiv:2410.20973) and our ongoing work together with J. E. Andersen and M. Kontsevich.

Orateur: Veronica Fantini (Université Paris-Saclay)

11:00 Coffee and Free Discussions

8 Large colour Wilson loops in N=4 SYM and Fredholm determinants

Orateur: Victor Mishnyakov (Nordita)

12:45 Déjeuner

9 Correlation functions in N=2 superconformal long quiver theories

Orateur: Alessandro Testa (IPhT CEA-Saclay)

15:30 Coffee and Free Discussions

10 Exact Three-Point Functions in N=2 Superconformal Field Theories

We propose an integrability approach for planar three-point functions at finite coupling in N=2 superconformal field theories obtained as Z_K orbifolds of N=4 super Yang-Mills (SYM). Generalising the hexagon formalism for N=4 SYM, we reproduce the structure constants of Coulomb branch operators, previously obtained by supersymmetric localisation, as exact functions of the 't Hooft coupling. Our analysis explains the common physical origin of Fredholm kernels in integrability and localisation, and hints at structures after the resummation in the hexagon formalism. This talk is based on arXiv:2503.07295 written with S. Komatsu, G. Lefundes, and D. Serban.

Orateur: Gwenael Ferrando (Bonn)

17:00 Free Discussions

ven. 12 décembre

11 Another 8 Loop Form Factor in Planar N=4 SYM

Orateur: Lance Dixon (CERN/SLAC)

12 Origin limits of large-charge correlators in planar N=4 SYM

Orateur: Benjamin Basso (Laboratoire de Physique de l'École Normale Supérieure)

11:00 Free Discussions

13 Bootstrapping six-point Yang-Mills amplitudes

Orateur: Dr Dmitry Chicherin (LAPTh, CNRS)

12:45 Déjeuner

14 Positivity Properties of Scattering Amplitudes

Positivity properties in quantum field theory (QFT) are often associated with fundamental principles such as unitarity and causality. Yet, in many cases, these properties arise from deeper mathematical structures.

In this talk, we explore an infinite set of positivity constraints obeyed by certain amplitudes—and related observables—that go beyond conventional expectations. Specifically, we highlight regions where these quantities and all of their signed derivatives are positive, a striking behavior known in mathematics as complete monotonicity. We begin by introducing completely monotone (CM) functions and their key properties, including their integral representations. We then demonstrate how fundamental objects in QFT, such as scalar Feynman integrals, exhibit this property. Building on this, we present evidence that a variety of observables—such as Coulomb branch amplitudes, the cusp anomalous dimension, and remainder functions in planar 𝑁=4 super Yang–Mills theory—exhibit complete monotonicity across multiple perturbative orders. We further show that some observables belong to an even more restricted subclass of CM functions, known as Stieltjes functions, which in particular allows for very good approximations of these observables using rational-functions.

We conclude by outlining potential applications of these constraints to the numerical bootstrap of Feynman integrals and to the ongoing study of positive geometries in quantum field theory.

Orateur: Prashanth Raman (MMPI)

15:30 Coffee and Free Discussions

15 The use of conformal Regge theory for high-order perturbative calculations

Orateur: Leonid Shumilov (University of Hamburg)

17:00 Free Discussions