Quantum enhancement to information speed

Sebastian Horvat, Borivoje Dakić

Published 2019-11-26Version 1

The speed of the transmission of a physical signal from a sender to a receiver is limited by the speed of light, regardless of the physical system being classical or quantum. In this sense, quantum mechanics can not provide any enhancement of the speed of information. If instead we consider that the information needing to be transmitted is not localized at the sender's location, but dispersed throughout space, spatial coherence might provide an enhancement of the information speed. In this work, we demonstrate a quantum mechanical advantage in the speed of acquirement and transmission of information globally encoded in space. Our findings can naturally be applied in situations where the information source has limited power, i.e. bounded number of signals that can be sent per unit time. We conclude by showing a significant advantage when using single photon (or Fock) states with respect to coherent states for communication purposes.