Josephson parametric amplifier based on superconducting-normal-superconducting junction

An amplifier, comprising:

• a resonant circuit, having a resonant frequency;
• a pump input;
• a signal input;
• and
• a signal output,
• the resonant circuit comprising a Josephson junction connected to the pump input,
• the Josephson junction being a superconducting-normal-superconducting junction having two superconducting terminals and being configured to adjust the resonant frequency of the resonant circuit based on a signal received at the pump input,
• wherein:
• the resonant circuit is a resonant transmission-line circuit comprising a first section of transmission line and a second section of transmission line, and
• the two superconducting terminals of the Josephson junction are connected in series between the first section of transmission line and the second section of transmission line.