Entanglement at room temperature in diamond
In a recent publication in Nature Nanotechnology, the group led by Jörg Wrachtrup experimentally demonstrated entanglement between two engineered single solid-state spin quantum bits (qubits) at ambient conditions. Photon emission of defect pairs reveals ground-state spin correlation. Entanglement (fidelity = 0.67±0.04) was proved by quantum state tomography. Moreover, the lifetime of electron spin entanglement was shown to be extended to milliseconds by entanglement swapping to nuclear spins. The experiments mark an important step towards a scalable room-temperature quantum device being of potential use in quantum information processing as well as metrology.