Frame-dragging effect manifests itself as polarization direction rotation
when linearly polarized electromagnetic/gravitational wave scatters from a
spinning point source through gravitational interactions. Treating general
relativity as an effective field theory, the polarization rotation angle and
its quantum corrections are computed using scattering amplitudes. While the
classical angle is universal as expected from the equivalence principle, the
quantum corrections are found to be different between electromagnetic and
gravitational waves, supporting earlier studies that some formulations of the
equivalence principle seem to be violated in the quantum regime.Comment: more accessible discussions, shortened abstract, updated references;
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