Fedorov Arkady, Kumar N Pradeep, Le Dat Thanh, Navarathna Rohit, Pakkiam Prasanna, Stace Thomas M
Analog Quantum Circuits Pty. Ltd., Brisbane, Australia and School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia.
Phys Rev Lett. 2024 Mar 1;132(9):097001. doi: 10.1103/PhysRevLett.132.097001.
Building large-scale superconducting quantum circuits will require miniaturization and integration of supporting devices including microwave circulators, which are currently bulky, stand-alone components. Here, we report the measurement of microwave scattering from a ring of Josephson junctions, with dc-only control fields. We detect the effect of quasiparticle tunneling, and dynamically classify the system at its operating design point into different quasiparticle sectors. We optimize the device within one of the quasiparticle sectors, where we observe an unambiguous signature of nonreciprocal 3-port scattering within that sector. This enables operation as a circulator, and at the optimal circulation point, we observe on-resonance insertion loss of 2 dB, isolation of 14 dB, power reflectance of -11 dB, and a bandwidth of 200 MHz, averaged over the 3 input ports.
构建大规模超导量子电路将需要对包括微波环行器在内的支持器件进行小型化和集成，而目前这些器件体积庞大且为独立元件。在此，我们报告了在仅施加直流控制场的情况下，对由约瑟夫森结构成的环的微波散射进行的测量。我们检测到了准粒子隧穿的效应，并在其工作设计点将系统动态分类到不同的准粒子扇区。我们在其中一个准粒子扇区内对器件进行了优化，在该扇区内我们观察到了明确的非互易三端口散射特征。这使得该器件能够用作环行器，在最佳环行点，我们观察到三个输入端口的平均共振插入损耗为2 dB、隔离度为14 dB、功率反射率为 -11 dB以及带宽为200 MHz。
