Superconducting quantum node for entanglement and storage of microwave radiation

Phys Rev Lett. 2015 Mar 6;114(9):090503. doi: 10.1103/PhysRevLett.114.090503. Epub 2015 Mar 4.


Superconducting circuits and microwave signals are good candidates to realize quantum networks, which are the backbone of quantum computers. We have realized a quantum node based on a 3D microwave superconducting cavity parametrically coupled to a transmission line by a Josephson ring modulator. We first demonstrate the time-controlled capture, storage, and retrieval of an optimally shaped propagating microwave field, with an efficiency as high as 80%. We then demonstrate a second essential ability, which is the time-controlled generation of an entangled state distributed between the node and a microwave channel.