arXiv subjects

Gianfranco De Simone

Publications and source records attributed to Gianfranco De Simone.

3 recordsLinked to original sources

arXiv2026

Higher spin dynamics in Weyl reference frame

In this manuscript we derive the $w_{1+\infty}$ algebra on an arbitrary null hypersurface located at finite distance. A straightforward integration of the evolution Bianchi identities is performed in a suitable dynamical reference frame, dubbed the Weyl reference frame. In this reference frame, the extraction of the (linear) higher spin charge bracket is similar to the asymptotic null case, except that the corner metric evolves non trivially in time. In other words, boundary degrees of freedom that are frozen at null infinity due to the boundary conditions now become part of the dynamics. This feature is reflected in the appearance of non-local terms in the brackets. In order to avoid the presence of these non-local terms in the charge bracket, we absorb this non-locality - which encodes nothing other than the history of the corner metric - into the definition of the higher spin charges. Moreover, a new perspective on the memory effect at finite distance is suggested. In conclusion, we believe that this treatment can also be applied to asymptotically (A)dS$_{4}$ spacetimes, where the presence of a non-vanishing cosmological constant leads to the introduction of a cosmological reference frame.

hep-th↗

arXiv2026

Near-Horizon Symmetries in Einstein-Maxwell theory

This manuscript aims to provide a comprehensive derivation of the Einstein-Maxwell charges and fluxes in the near-horizon region of a four-dimensional non-extremal black hole, with vanishing cosmological constant. Specifically, we present a detailed derivation of the Noether charges within both the metric and first-order formulations, elucidating the relationship between the Carrollian internal boost charge and the Lorentz boost charge. It is well-established in the literature that Carrollian fluids exhibit an internal local boost symmetry; we demonstrate that this symmetry precisely corresponds to a Lorentz internal transformation. Finally, we prove that the near-horizon Einstein equations can be obtained from the flux-balance law by employing the generalized Barnich-Troessaert bracket.

hep-th↗

arXiv2026

Duality symmetry and dynamics on finite null boundaries

In this work, we derive a set of boost-weighted $w$ functionals of the metric, with $w\in\{2,1,0,-1,-2\}$, which transform semi-covariantly under the action of the near-horizon symmetry group. In particular, we demonstrate that the knowledge of the $w=-2$ metric functional and its behaviour under the near-horizon symmetry transformations allows us to derive the expressions and the properties of the remaining boost-weighted functionals via a recursive pattern. A similar recursive pattern also appears when evaluating the action of the near-horizon symmetry group on the evolution equations of these boost-weighted functionals. Again, the knowledge of the evolution equation of the boost $w=-2$ functional and its behaviour under symmetry transformations allows the remaining evolution equations to be determined using symmetry arguments. We also emphasize the role played by the duality symmetry in the characterization of the phase space of a null boundary and in the evaluation of the equation of motion. In conclusion, we derive the sub-leading Noether charges in the Einstein-Cartan-Holst formulation of gravity, showing that the imaginary part of the Weyl scalar $Ψ_2$ appears at the sub-leading order in the Holst charge.

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