Renormalization of spin-one asymptotic charges in AdSD

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We provide holographic realisations in Minkowski spacetime of a free conformal Carrollian scalar field living at null infinity. To this end, we first show that the electric and magnetic limits of a relativistic conformal scalar are equivalent and we study the representation of the Carroll, Poincaré and BMS algebras that is realised on the resulting solution space. We then realise it as a quotient of the solution space of a free massless scalar in Minkowski spacetime with unusual falloff, in full analogy with the interpretation of Dirac’s singleton as a shortened scalar in Anti de Sitter spacetime.

Section: Jhep05(2024)242mentioning

confidence: 99%

Holographic Carrollian conformal scalars

Bekaert,

Campoleoni,

Pekar

2024

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Flat space spinning massive amplitudes from momentum space CFT

Marotta,

Skenderis,

Verma

2024

We discuss the flat space limit of AdS using the momentum space representation of CFT correlators. The flat space limit involves sending the AdS radius and the dimensions of operators dual to massive fields to infinity while also scaling appropriately the sources of the dual operators. In this limit, d-dimensional CFT correlators become (d + 1)-dimensional scattering amplitudes. We exemplify our discussion with the computation of the flat-space limit of the CFT 3-point function of a conserved current, a non-conserved charged vector operator and its conjugate. The flat-space limit should yield the scattering amplitude of an Abelian gauge field with two massive vector fields. This scattering amplitude computes the electromagnetic form factors of the electromagnetic current in a spin-1 state, and these form factors encode the electromagnetic properties of the massive vector field (charge, magnetic moment and quadruple moment). In terms of the CFT, the flat-space limit amounts to zooming in the infrared region of the triple-K integrals that determine the 3-point function, while also scaling to infinity the order of (some of) the Bessel functions that feature in the triple-K integrals. In this limit the triple-K integral becomes proportional to the energy-preserving delta function, and the flat space limit correctly yields the corresponding flat space scattering amplitude in complete detail.

$$ \mathcal{O} $$(rN) two-form asymptotic symmetries and renormalized charges

Romoli

2024

We investigate $$ \mathcal{O} $$ O (rN) asymptotic symmetries for a two-form gauge field in four-dimensional Minkowski spacetime. By employing symplectic renormalization, we identify N independent asymptotic charges, with each charge being parametrised by an arbitrary function of the angular variables. Working in Lorenz gauge, the gauge parameters require a radial expansion involving logarithmic (subleading) terms to ensure nontrivial angular dependence at leading order. At the same time, we adopt a setup where the field strength admits a power expansion, allowing logarithms in the gauge field expansions within pure gauge sectors. The same setup is studied for electromagnetism.