Expanding Interferometry’s Potential with Quantum Memory

Why It Matters

Quantum‑assisted interferometry promises higher‑resolution astronomy without the massive structures traditionally required, opening cost‑effective pathways for next‑generation telescopes and space missions.

Key Takeaways

• Harvard team achieved quantum‑teleported interference over 1.55 km baseline.
• Baseline exceeds CHARA’s 330 m, approaching long‑baseline interferometry scale.
• Quantum memories store photon info, eliminating photon‑loss in transport.
• Potential to shrink space telescopes, saving billions on future missions.
• Scaling to dozens of memories needed for practical astronomical imaging.

Pulse Analysis

Optical interferometry has long been limited by the need to physically combine light from separate telescopes, a process that becomes increasingly lossy as baselines grow. Quantum memories—tiny diamond chips that can store photon states in entangled electron and nuclear spins—offer a way around this bottleneck. By converting incoming photons into quantum information and teleporting that data across a fiber link, researchers can reconstruct interference patterns without moving the photons themselves, preserving signal fidelity over distances that would otherwise degrade the image.

In a recent demonstration, Lukin’s group at Harvard used two such memories linked by 1.55 km of spooled fiber, achieving an interference pattern from weak laser light that simulates starlight. This baseline is roughly five times longer than the CHARA array’s 330 m, marking a significant step toward optical long‑baseline interferometry that rivals radio‑frequency networks like the Event Horizon Telescope. The experiment also showcases quantum teleportation of photon states, eliminating the photon‑loss that plagues conventional beam‑combining methods and allowing for a non‑local measurement that does not deteriorate with distance.

Looking ahead, the technology could dramatically shrink the physical footprint of future observatories. NASA’s Habitable Worlds Observatory team is already exploring quantum‑enhanced designs that could deliver large‑aperture performance from a modest‑size telescope, potentially saving billions in launch and construction costs. However, practical deployment will require scaling the system to dozens of memories per site, improving network stability, and increasing photon‑collection rates. If these hurdles are overcome, quantum‑assisted interferometry could become a cornerstone of high‑resolution imaging for exoplanet characterization, stellar surface mapping, and beyond.