Jack Y. Qiu, Arne Grimsmo, Kaidong Peng, Bharath Kannan, Benjamin Lienhard, Youngkyu Sung, Philip Krantz, Vladimir Bolkhovsky, Greg Calusine, David Kim, Alex Melville, Bethany M. Niedzielski, Jonilyn Yoder, Mollie E. Schwartz, Terry P. Orlando, Irfan Siddiqi, Simon Gustavsson, Kevin P. O’Brien & William D. Oliver

DOI: 10.1038/s41567-022–01929‑w


Squeezing of the electromagnetic vacuum is an essential metrological technique used to reduce quantum noise in applications spanning gravitational wave detection, biological microscopy and quantum information science. In superconducting circuits, the resonator-based Josephson-junction parametric amplifiers conventionally used to generate squeezed microwaves are constrained by a narrow bandwidth and low dynamic range. Here we develop a dual-pump, broadband Josephson travelling-wave parametric amplifier that combines a phase-sensitive extinction ratio of 56 dB with single-mode squeezing on par with the best resonator-based squeezers. We also demonstrate two-mode squeezing at microwave frequencies with bandwidth in the gigahertz range that is almost two orders of magnitude wider than that of contemporary resonator-based squeezers. Our amplifier is capable of simultaneously creating entangled microwave photon pairs with large frequency separation, with potential applications including high-fidelity qubit readout, quantum illumination and teleportation.