A design for a new broad-bandwidth amplifier for detecting single microwave photons has been unveiled by physicists at the University of California, Berkeley and the Lawrence Berkeley National Laboratory in the US. The "Josephson travelling-wave parametric amplifier" uses a technique called "resonant phase matching", which is expected to boost the gain in the amplifier by more than 10 dB compared with existing Josephson parametric amplifiers (JPAs). The new device is also predicted to have a bandwidth of 3 GHz, and together these properties should allow it be used in quantum circuits that operate at multiple frequencies, as well as finding use in extremely sensitive astronomical detectors.

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