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## Full-Text Articles in Physics

Graviton-Photon Scattering, N.E.J. Bjerrum-Bohr, Barry R. Holstein, Ludovic Planté, Pierre Vanhove

#### Graviton-Photon Scattering, N.E.J. Bjerrum-Bohr, Barry R. Holstein, Ludovic Planté, Pierre Vanhove

*Barry R Holstein*

We use the feature that the gravitational Compton scattering amplitude factorizes in terms of Abelian QED amplitudes to evaluate various gravitational Compton processes. We examine both the QED and gravitational Compton scattering from a massive spin-1 system by the use of helicity amplitude methods. In the case of gravitational Compton scattering we show how the massless limit can be used to evaluate the cross section for graviton-photon scattering and discuss the difference between photon interactions and the zero mass spin-1 limit. We show that the forward scattering cross section for graviton photoproduction has a very peculiar behavior, differing from the ...

Bending Of Light In Quantum Gravity, N.E.J. Bjerrum-Bohr, John F. Donoghue, Barry R. Holstein, Ludovic Planté, Pierre Vanhove

#### Bending Of Light In Quantum Gravity, N.E.J. Bjerrum-Bohr, John F. Donoghue, Barry R. Holstein, Ludovic Planté, Pierre Vanhove

*Barry R Holstein*

We consider the scattering of lightlike matter in the presence of a heavy scalar object (such as the Sun or a Schwarzschild black hole). By treating general relativity as an effective field theory we directly compute the nonanalytic components of the one-loop gravitational amplitude for the scattering of massless scalars or photons from an external massive scalar field. These results allow a semiclassical computation of the bending angle for light rays grazing the Sun, including long-range ℏ contributions. We discuss implications of this computation, in particular the violation of some classical formulations of the equivalence principle.