On-sky recovery of astronomical visibility

Demonstrate whether an entangled-reference or memory-assisted quantum interferometry protocol can recover a calibrated stellar visibility on the sky that agrees with conventional direct detection.

Background

The review states that existing demonstrations used laboratory sources rather than astronomical light. A first observation with spatially filtered sunlight and subsequently with a bright star would test coupling, atmospheric piston, delay tracking, calibration, and the end-to-end performance of the quantum receiver under observatory conditions.

References

It remains to be seen whether exploiting $N00N$ states is realistic for astronomical observations.

— Progress in quantum telescopes  (2609.18079 - Gozzard et al., 16 Sep 2026) in Section 5.1, “Optimal imaging with quantum interferometers”

However, no simulations of what astronomical science is achievable with current technology (i.e. 10~m-class telescopes and wavelengths limited to the telecommunications C-band) have yet been performed, so there remain open questions as to the near-term practicality of this technology for astronomy.

— Progress in quantum telescopes  (2609.18079 - Gozzard et al., 16 Sep 2026) in Section 5.1, “Optimal imaging with quantum interferometers”

Can we recover a visibility on the sky? Apply an entangled-reference or memory-assisted protocol first to spatially filtered sunlight as a receiver test and then to a bright star. Does the calibrated stellar visibility agree with conventional direct detection?

— Development of quantum technologies for optical/infrared interferometry  (2609.04311 - Monnier, 3 Sep 2026) in Section 7, “Next experiments,” item 1

What are the practical challenges of separate telescope operation? Place nodes at physically separated telescopes and track geometric delay and piston while preserving nonlocal heralding and path erasure.

— Development of quantum technologies for optical/infrared interferometry  (2609.04311 - Monnier, 3 Sep 2026) in Section 7, “Next experiments,” item 2

Does a complete quantum experiment win in a science measurement? Choose a narrow case, perhaps stellar-diameter visibility, binary astrometry, or geodesy, and compare observing time and systematic error against HBT, heterodyne, and direct detection using the same apertures.

— Development of quantum technologies for optical/infrared interferometry  (2609.04311 - Monnier, 3 Sep 2026) in Section 7, “Next experiments,” item 5