Researchers have proposed a mode of quantum communication whereby information could travel between two parties without the exchange of physical particles.

Quantum communication holds the promise of ultrasecure encryption, but most schemes proposed so far require the communicating parties to exchange particles. Hatim Salih at King Abdulaziz City for Science and Technology in Riyadh, Saudi Arabia, and his colleagues suggest a scheme in which a photon kept by one party is influenced by the other party opening or closing a channel between them. In principle, this allows for a measurement that can securely convey information without transferring or exchanging physical particles. This challenges long-standing assumptions of the requirements for communication, the authors say.

Phys. Rev. Lett. 110, 170502 (2013)