Bellazzini, BrandoIsabella, GiuliaLewandowski, MatthewSgarlata, Francesco2022-06-062022-06-062022-06-062022-05-2410.1007/JHEP05(2022)154https://infoscience.epfl.ch/handle/20.500.14299/188378WOS:000800150600005We study causality in gravitational systems beyond the classical limit. Using on-shell methods, we consider the 1-loop corrections from charged particles to the photon energy-momentum tensor - the self-stress - that controls the quantum interaction between two on-shell photons and one off-shell graviton. The self-stress determines in turn the phase shift and time delay in the scattering of photons against a spectator particle of any spin in the eikonal regime. We show that the sign of the beta-function associated to the running gauge coupling is related to the sign of time delay at small impact parameter. Our results show that, at first post-Minkowskian order, asymptotic causality, where the time delay experienced by any particle must be positive, is respected quantum mechanically. Contrasted with asymptotic causality, we explore a local notion of causality, where the time delay is longer than the one of gravitons, which is seemingly violated by quantum effects.Physics, Particles & FieldsPhysicseffective field theoriesscattering amplitudesquantum-electrodynamic correctionsgravityfieldtext::journal::journal article::research article