Two-photon amplitude interferometry for precision astrometry

Improved quantum sensing of photons from astronomical objects could provide high resolution observations in the optical benefiting numerous fields, including general relativity, dark matter studies, and cosmology. It has been recently proposed that stations interferometers would not require a phase-stable link if instead sources quantum-mechanically entangled pairs be provided to them, potentially enabling hitherto prohibitively long baselines. A new refinement this idea is developed, which two different are interfered at separate decoupled stations, requiring only slow classical information between them. We rigorously calculate observables contrast interferometric technique with Hanbury Brown \& Twiss intensity interferometry. argue allow robust high-precision measurements relative astrometry sources. basic calculation suggests angular precision on order $10$ microarcseconds opening angle achieved single night's observation bright stars.