Optical fibres may transport quantum information, say researchers

In their experiment, the researchers trapped a calcium ion in an ion trap and positioned it between two highly reflective mirrors. A laser was then used to write the desired quantum information onto the electronic states of the atom. A second laser was used to excite the atom, resulting in a photon being emitted. The atom's quantum information is written onto the the photon, which is stored between the mirrors until it eventually leaves the ion trap and into the optical fibre. The researchers believe that quantum information stored in the photon could be sent to a distant quantum computer, where the same technique could be applied in reverse to write it back onto an atom. "Currently, we can carry out successful quantum computations with atoms," explained Andreas Stute and Bernardo Casabone, both PhD students at the University of Innsbruck's Institute for Experimental Physics. "But we are still missing viable interfaces with which quantum information can be transferred over optical channels from one computer to another."