Science Daily February 2, 2023
Trapped ions are one of the leading systems to build quantum computers and other quantum technologies. To link multiple such quantum systems, interfaces are needed through which the quantum information can be transmitted. An international team of researchers (Austria, USA – Georgetown University, Switzerland, France) has demonstrated an elementary quantum network of two atomic ions separated by 230 m. The ions were trapped in different buildings and connected with 520(2) m of optical fiber. At each network node, the electronic state of an ion was entangled with the polarization state of a single cavity photon; after interference of the photons at a beam splitter, photon detection shows entanglement between the two ions. Fidelities of up to (88.0+2.2−4.7) % were achieved with respect to a maximally entangled Bell state, with a success probability of 4×10−5. They analyzed the routes to improve these metrics, paving the way for long-distance networks of entangled quantum processors…read more. TECHNICAL ARTICLE
The two-node quantum network. Credit: Phys. Rev. Lett. 130, 050803, 2 February 2023