Orateur
Description
The BMS group is the symmetry group at infinity of asymptotically flat spacetimes. In the presence of gravitationnal radiation, the associated Noether currents at null infinity are linked through flux-balance laws to variations of global quantities of the system, such as energy and angular momentum. I will present how, using the Noether currents fixed through a specific Wald-Zoupas prescription, which already enabled the obtention of background independent BMS charges, the charge integrands were obtained. Being obtained as 2-forms, those integrands, referred to as charge aspects, enable integration of the charges over a generic cross-section of null infinity, and not simply one at a constant retarded-time coordinate. I will then show why the shape of those aspects, which correspond to charge densities, suggest that the notion of a stress-energy tensor at infinity is not appropriate. Finally I will discuss the background dependence of the aspects, and notably the central extension that they exhibit.
| Which working group does your abstract concern? | Formes d'ondes / Waveforms |
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