Georgia Tech researchers make quantum networking progress

Earlier work has seen atoms entangled with spontaneously emitted light, but because the photons were generated infrequently, it took a relatively long time to create entanglement. This limited the potential quantum network to two nodes. Looking to develop multinode quantum networks, researchers are working on the entanglement between light and atoms in quantum states. Following a suggestion from colleagues at the University of Wisconsin, a team at Georgia Tech has developed a state insensitive optical trap that can confine ground state and Rydberg rubidium atoms coherently. Rydberg atoms have a radius of about 1µm, which gives them exaggerated electromagnetic properties and allows them to interact strongly with one another. The trap can confine atoms for up to 80ms – said to be long enough to operate complex protocols that might be part of a quantum network. "The system we have realised is closer to being a node in a quantum network than what we have been able to do before," said Alex Kuzmich, a professor of physics at Georgia Tech. "It is certainly a promising improvement." The rate of generating entangled photons has been increased from a few photons per second with earlier approaches to as many as 5000 photons per second with the new technique. The Quantum Memories Multidisciplinary University Research Initiative (MURI) is supported by the US Air Force Office of Scientific Research. The consortium brings together seven US universities to determine the best approach for creating quantum memories based on the interaction between light and matter. Three concepts are being pursued for creating entangled quantum memories that could enable secure information to be transmitted over long distances.