A protocol for synchronizing distant clocks is proposed that does not rely on the arrival times of the signals which are exchanged, and an optical implementation based on coherent-state pulses is described. This protocol is not limited by any dispersion that may be present in the propagation medium through which the light signals are exchanged. Possible improvements deriving from the use of quantum-mechanical effects are also addressed.
@article{arxiv.quant-ph/0405154,
title = {Conveyor belt clock synchronization},
author = {Vittorio Giovannetti and Seth Lloyd and Lorenzo Maccone and Jeffrey H. Shapiro and Franco N. C. Wong},
journal= {arXiv preprint arXiv:quant-ph/0405154},
year = {2009}
}