Electromagnetic radiation in flat and de Sitter spacetimes

by Iñaki Zalduendo (Universidad de La Plata)

Thursday 9 Apr 2026, 14:15 → 15:15 Europe/Berlin

We explore properties of electromagnetic radiation in de Sitter spacetime. To set the stage we revisit the more familiar case of electromagnetic radiation in flat spacetime using Bondi coordinates. The corresponding analysis in de Sitter spacetime leads to the counterintuitive result that the energy of the system may increase in the presence of radiation. To clarify this puzzle, we revisit the notion of energy in de Sitter space through the explicit example of a radiating dipole, which provides a physically transparent framework to address these conceptual challenges. We identify the notion of news and memory vector as a combination of components of the electromagnetic tensor.