Science Daily March 22, 2022
An international team of researchers (Switzerland, France) has stored a qubit for 20 milliseconds in crystals doped with europium capable of absorbing light and then re-emitting it. They managed to reach the 100-millisecond mark with a small loss of fidelity. The crystals were kept at -273,15°C, because beyond 10°C above this temperature, the thermal agitation of the crystal destroys the entanglement of the atoms. In theory, it would be enough to increase the duration of exposure of the crystal to radio frequencies, but for the time being, technical obstacles to their implementation over a longer period prevented them from going beyond 100 milliseconds. They must find ways of designing memories capable of storing more than a single photon at a time, and thus of having ‘entangled’ photons which will guarantee confidentiality. The work is a major advance for the development of long-distance quantum telecommunications networks, and it brings the storage of a quantum state carried by a photon to a time scale that can be estimated by humans…read more. Open Access TECHNICAL ARTICLE
System and setup. Credit: npj Quantum Information volume 8, Article number: 29 (2022)Â