Gravitational redshift of broadband relativistic quantum photons

Abstract:Gravitational redshift is a key prediction of general relativity that has been experimentally verified. Nevertheless, its existence in the context of relativistic and quantum physics has not yet been established. We employ linearized quantum gravity to study the effects of quantum coherence on gravitational redshift of broadband photons that interact with a planet via graviton exchange. We find that gravitational redshift, as predicted by general relativity, occurs when the initial photonic state contains no quantum coherence between orthogonal photonic modes, such as position states. If quantum coherence is initially present, different photonic modes overlap, a genuine quantum correction occurs solely for single-photon states. Our work not only explains gravitational redshift as the interaction of gravitons and photons in flat spacetime, but also shows that deviations from the theory occur already at low energies when quantum interference of photonic states is important.

12 pages, 1 figures. Comments welcome

arXiv:2504.03956 [gr-qc]

(or arXiv:2504.03956v3 [gr-qc] for this version)

https://doi.org/10.48550/arXiv.2504.03956 Focus to learn more arXiv-issued DOI via DataCite

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