arXiv:2609.11974
Do Quantum Measurement Advantages Survive to Astrophysical Inference? Seven Benchmarks in Optical Interferometry and Imaging
Slava G. Turyshev
Abstract
Quantum techniques matter to optical astronomy when they preserve information in the parameter-bearing measurement channel after realistic loss, calibration, covariance, and inference are propagated to the final astrophysical observable. We compare 7 approaches by the quantity they change: internal optical-path delay, sub-Rayleigh source separation, coronagraphic planet throughput & stellar leakage, coherent field quadratures, nonlocal complex visibility, null depth, active phase sensing. In an Earth-analog astrometry case, 6-dB squeezed internal metrology improves the measured phase quadrature by 1.58 and the complete readout by ~1.20, but fixed-time planet-mass precision by only 1.010 (95 % interval 1.005-1.045); mission duration, useful baseline, cadence, calibration have greater modeled leverage. For a close young binary, signed spatial-mode demultiplexing preserves sub-Rayleigh orbital information that is substantially degraded in the tested direct-imaging comparator. A representative matched-model calculation gives a dynamical-mass RMSE gain 1.77 1.47-2.15). For illustrative equal-prior pre-main-sequence predictions at 0.10 and \(0.12M_\odot\), mass precisions of 15%, 10%, 7% correspond to correct-selection probabilities of ~73%, 82%, 90%. The numerical gain remains provisional because the event-level continuous-image comparator, strict tail convergence, externally measured broadband transfer matrix, and finite-photon calibration are not yet closed. Modal coronagraphy and quantum-enhanced heterodyne reception define conditional receiver opportunities, while the nonlocal, nuller, and prepared-NOON cases identify physical bottlenecks that prevent an astrophysical advantage in the stated configurations. The common result is that quantum technology is most valuable when it changes an information-bearing observable and that channel remains consequential in the final science measurement.