美国麻省理工学院Jack Y. Qiu和William D. Oliver团队在研究中取得进展。他们研究了宽带压缩微波和约瑟夫森行波参量放大器的放大。2023年2月9日出版的《自然—物理学》发表了这项成果。

研究人员开发了一个双泵浦，宽带约瑟夫森行波参量放大器，它结合了56 dB的锁相消光比和单模压缩，与最好的基于谐振器的压缩器相当。该团队还演示了微波频率的双模压缩，带宽在千兆赫兹范围内，几乎比当代基于谐振器的压缩器宽两个数量级。他们的放大器能够同时产生具有大频率间隔的纠缠微波光子对，具有潜在的应用包括高保真量子位读取，量子照明和量子隐形传态。

研究人员表示，电磁真空压缩是一项重要的计量技术，旨在降低引力波探测、生物显微镜和量子信息科学等领域的量子噪声。在超导电路中，基于谐振腔的约瑟夫森结参数放大器通常用于产生压缩微波，但受制于窄带宽和低动态范围。

附：英文原文

Title: Broadband squeezed microwaves and amplification with a Josephson travelling-wave parametric amplifier

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

Issue&Volume: 2023-02-09

Abstract: 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 56dB 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.

DOI: 10.1038/s41567-022-01929-w

Source: https://www.nature.com/articles/s41567-022-01929-w