QuReP News

A quantum wedding of two crystals

Quantum networks require the crucial ability to entangle quantum nodes. A prominent example is the quantum repeater, the central theme of the QuReP project, which allows overcoming the distance barrier of direct transmission of single photons, provided remote quantum memories can be entangled in a heralded fashion. Building on our recent progress with quantum memories based on rare-earth-ions-doped crystals, The Geneva group have recently demonstrated heralded entanglement between two quantum nodes. The entanglement is created by storing a spatially delocalised heralded single photon state into the memories. Then, the entanglement is revealed by mapping it back to optical modes and by performing quantum state tomography on the retrieved state. Our results show that two macroscopic crystals can be entangled together in an heralded fashion. This brings quantum networks based on solid-state devices one step closer. For more technical information you can find the paper in Nature Photonics.