The talk will present our experimental roadmap for satellite-to-ground single-photon interference. I will first discuss our 2024 terrestrial experiment over an 8.4 km horizontal atmospheric link, in which we demonstrated long-baseline single-photon interference using unbalanced Michelson interferometers.
I will then describe our plans to extend the experiment to satellite-to-ground links using medium- and high-Earth-orbit satellites, to directly probe the gravitational redshift with single-photon interference and test quantum interference in curved spacetime.
Finally, I plan to discuss several related ideas for quantum-optical probes of gravity, including Hong–Ou–Mandel interference and possible experiments exploring the interplay between entanglement and gravity.