Quantum technologies operating at microwave technologies, such as Rare Earth ion memories and superconducting circuits, must work at cryogenic temperatures to avoid thermal photons. As a consequence, efficiently extracting a signal from these systems requires quantum limited amplification. Such amplifiers rely on the non-lineariry of the Josephson junctions, lossless superconducting tunneling junctions.
In our group, LI Ye and Jagadesh RANGARAJ are looking at fabrication techniques towards developing amplifiers.