In a proposed communication scheme, quantum entanglement and quantum nonlocality would be utilized to effect instantaneous transmission of randomly chosen messages to remote locations. Although the messages would not convey any information, they might nevertheless be of some value under circumstances in which deception and secrecy are of more importance than are the specific contents of the messages.
The scheme would be implemented in a simple quantum algorithm: The sender and recipient would each possess n particles, each of which could be in one of two equally probable quantum states denoted "+" and "–" (e.g., corresponding to spin up or spin down if the particles were electrons). Each particle at the sender's location would be paired with one of particles at the recipient's location by a quantum entanglement.
The sender and recipient would both perform a timed sequence of measurements on their particles — one particle per time step — so that at the end of n time steps, the sender and recipient would both possess n-length sequences of "+" and "–" readings. By performing the measurements, the sender would have randomly selected one of the 2n possible sequences. The sequence would constitute a randomly chosen message. Because of quantum entanglement, the recipient's sequence would be uniquely correlated with the sender's sequence.
Given the randomness of the selection, the message would convey no information. The message may nevertheless have value under circumstances in which any of the 2n possible messages would be equally effective in producing a desired outcome and there is a requirement to keep the message (that is, the randomly chosen sequence of "+" and "–" secret from everyone except the intended recipient. In such circumstances, the value would lie in secrecy and/or deception: the random selection would hide the actual message among 2n–1 other messages.
This work was done by Michail Zak of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Information Sciences category.