Five-Photon Entanglement Could Benefit Quantum Communications

Emerging strategies for distributed quantum information processing will require some type of teleportation protocol. One option is open-destination teleportation, where an unknown quantum state of a single particle is teleported onto a superposition of other particles and then read out at a later stage at any of those particles.

Working with colleagues at the University of Innsbruck in Austria and Heidelberg University in Germany, scientists at the University of Science and Technology in China recently demonstrated a five-photon entanglement technique that can be used for a proof-of-concept of this teleportation scheme. They also believe the technique could help demonstrate bit-flip error rejection for quantum communications.

The setup, which is described in the July 1 issue of Nature, uses two Einstein-Podolsky-Rosen entangled photon sources, each emitting one polarization-entangled photon pair, to generate a four-photon entangled state. This combined with a single-photon state makes it possible to observe five-photon entanglement as long as only one photon is detected in each of the five output modes.