Entanglement-assisted non-local optical interferometry in a quantum network
Pieter-Jan Stas, Y.-C. Wei, Maxim A. Sirotin, Yan Qi Huan, Umut Yazlar, F. A. Arias, E. Knyazev, Gefen Baranes, Bartholomeus Machielse, Samuele Grandi, D. Riedel, Johannes Borregaard, H. Y. Park, Marko Lončar, A. Suleymanzade, M. D. Lukin · Nature · 2026
The sensitivity of non-local optical measurements at low light intensities, such as those involved in long-baseline telescope arrays1,2, is limited by fundamental quantum noise and photon losses3. Distributed quantum entanglement has been proposed as a route towards overcoming these limitations and accessing new regimes of non-local optical sensing4–6. Here we demonstrate the use of entangled quantum memories in a quantum network of silicon–vacancy centres in diamond nanocavities7–9 to experimentally perform such non-local phase measurements. Specifically, we combine the generation of event-ready remote quantum entanglement, photon mode erasure that hides the ‘which-path’ information of temporally and spatially separated incoming optical modes and non-local, non-destructive photon heralding enabled by remote entanglement to perform a proof-of-concept entanglement-assisted differential phase measurement of weak incident light between two spatially separate stations. Demonstrating successful operation of the remote phase sensing protocol with a fibre link baseline up to 1.55 km, our results provide an opportunity for a new class of quantum-enhanced optical imaging methods with potential applications ranging from long-baseline interferometry and astronomy to microscopy10,11. Entangled quantum memories are used in a quantum network of silicon–vacancy centres in diamond nanocavities to experimentally perform non-local phase measurements.