Physicists, involved in Quantum Networks developments, are looking for ways to transfer quantum information between matter and light using entanglement, a property in which the state of one particle depends on the state of a second ones.

At the University of Innsbruck they have developed and tested a prototype of interface between light and matter for future quantum processing and networking.

The experimental device traps a single calcium ion in a Paul trap and places it between two highly mirrors. The ion is excited with a laser, thus generating a photon entangled with the ion and reflected back and forth by the mirrors. Interestingly, the frequency and amplitude of the laser can be tuned so that the target collective state of the ion and photon is reached.

Experimental apparatus

“Whenever we have to transfer quantum information from processing sites to communication channels, and vice versa, we’re going to need an interface between light and matter” explains the Physicists.

The experiment is impressive as it offers important practical insights into the interaction of light and matter: another step towards quantum computers or future quantum networks.

Ref.: A. Stute, B. Casabone, P. Schindler, T. Monz, P. O. Schmidt, B. Brandstätter, T. E. Northup, R. Blatt, Tunable Ion-Photon Entanglement in an Optical Cavity, Nature, 2012, DOI: 10.1038/nature11120