Iterative quantum algorithm for distributed clock synchronization

Clock synchronization is a well-studied problem with many practical and scientific applications. We propose an arbitrary accuracy iterative quantum algorithm for distributed clock synchronization using only three qubits. The n bits of the time difference Δ between two spatially separated clocks can be deterministically extracted by communicating only O(n) messages and executing the quantum iteration process n times based on the classical feedback and measurement operations. Finally, we also give the algorithm using only two qubits and discuss the success probability of the algorithm.