Quantum Time Transfer: A Practical Method for Lossy and Noisy Channels

Precise clock synchronization is important for quantum networking, enhanced position, navigation, timing, and other applications that require clock synchronization better than GPS, but remains an ongoing challenge. The authors propose a solution using hardware native to quantum networking. This quantum-time-transfer technique can quickly achieve picosecond-level clock synchronization despite relatively low-performance quantum-photon sources and detection equipment. Furthermore, it is robust against the high loss and high noise channel conditions representative of daytime space-Earth links, and could provide high-precision secure timing in GPS-denied environments.