Abstract: Methods and systems for synchronizing a first clock with a second clock, wherein the clocks are separated, are disclosed. A representative system, among others, includes a correlated particle emitter that emits a first particle stream and a second particle stream. Particles in the first particle streams are quantum mechanically correlated with particles in the second particle stream. The system also includes: a first target having the first clock and a first particle detector, and a second target having the second clock and a second particle detector. The first target uses the first clock and the first particle detector to determine arrival times of particles included in the first particle stream, and the second target uses the second clock and the second particle detector to determine arrival times of particles included in the first particle stream.