Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2023-2024

Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge

05 - Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge : Anomalies et renormalisation des théories de Yang-Mills ; renormalisabilité au sens de Weinberg

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2023-2024

Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge

04 - Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge : Cohomologie BRST locale

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2023-2024

Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge

03 - Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge : Déformations classiques des théories de jauge

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2023-2024

Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge

02 - Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge : Équations maîtresses classique et quantique

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2023-2024

Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge

01 - Formalisme des antichamps, cohomologie BRST et renormalisation des théories de jauge : Formalisme des antichamps et symétrie BRST – principes généraux

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2022-2023

La structure asymptotique de l'espace-temps (II)

Séminaire - Marios Petropoulos : Charges and Dual Charges – a Carrollian Perspective

Intervenant(s)

Marios Petropoulos, École Polytechnique, Palaiseau, France

Carroll geometries emerge as conformal boundaries of asymptotically flat spacetimes and have come to the forefront with the advent of flat holography. I will introduce these tools, which encompass the Carrollian descendants of the Cotton tensor, and show how they are used for generating towers of electric and magnetic charges. This approach sets the appropriate framework for unravelling the boundary local manifestation of hidden electric/magnetic duality symmetries such as Ehlers' Möbius symmetry present in four-dimensional Ricci-flat spacetimes that enjoy an isometry.

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2022-2023

La structure asymptotique de l'espace-temps (II)

Séminaire - Massimo PorratI : Supertranslation-Invariant Definitions of the Angular Momentum Flux in General Relativity

Intervenant(s)

Massimo Porrati, New York University, USA

The canonical definition of the angular momentum flux in the Bondi formalism of general relativity transforms under supertranslations. These correspond to gravitational waves of infinite wavelength – or, quantum mechanically, to zero-energy gravitons. New definitions of the angular momentum flux have been proposed in the literature that are invariant under supertranslations. They are nonlocal in the gravitational field but physically consistent. Some of them nevertheless fail to reproduce the change in angular momentum of a gravitational system undergoing scattering with emission of gravitational waves even at the lowest order in the Newton constant G.

After a brief review of relevant earlier results, I will propose a definition of angular momentum and angular momentum flux that reproduces perturbative results in gravitational scattering, is conserved, closes the correct algebra under Poisson brackets, and reduces to the standard expressions in non-radiating spacetimes.

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2022-2023

La structure asymptotique de l'espace-temps (II)

Séminaire - Andrea Puhm : Asymptotic Symmetries and Celestial Conformal Field Theory

Intervenant(s)

Andrea Puhm, École Polytechnique, Palaiseau, France

Novel insights into the asymptotic structure at null infinity suggest a holographic principle for spacetimes with (nearly) flat asymptotics: bulk scattering processes may be encoded in a lower-dimensional theory living on the celestial sphere at the null boundary of the spacetime. In this "celestial conformal field theory" the bulk S-matrix is recast as a conformal correlation function of Lorentz or boost eigentstates. Harnessing the power of CFT, I will explain how asymptotic symmetries at null infinity can be understood from the universal structure of soft theorems in quantum field theory together with conformal representation theory. Identifying the symmetries is a crucial first step in establishing the "celestial holography" program and I will discuss some of the recent developments in this direction.

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2022-2023

La structure asymptotique de l'espace-temps (II)

06 - La structure asymptotique de l'espace-temps (II) : Moment cinétique et supertranslations – Triangle infrarouge

Marc Henneaux

Collège de France

Champs, cordes et gravité

Année 2022-2023

La structure asymptotique de l'espace-temps (II)

Séminaire - Glenn Barnich : Coadjoint Representation and Geometric Action for the BMS Group

The coadjoint representation of the BMS4 group is constructed and related to the conserved current algebra of non-radiative asymptotically flat spacetimes at null infinity. The associated geometric action is a field theory in two plus one dimensions whose Poisson bracket algebra of Noether charges realizes the BMS4 Lie algebra.

Glenn Barnich, Université Libre de Bruxelles, Belgique