Partanen M, Tan K Y, Masuda S, Govenius J, Lake R E, Jenei M, Grönberg L, Hassel J, Simbierowicz S, Vesterinen V, Tuorila J, Ala-Nissila T, Möttönen M
QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 13500, FI-00076, Aalto, Finland.
National Institute of Standards and Technology, Boulder, Colorado, 80305, USA.
Sci Rep. 2018 Apr 20;8(1):6325. doi: 10.1038/s41598-018-24449-1.
Superconducting microwave circuits show great potential for practical quantum technological applications such as quantum information processing. However, fast and on-demand initialization of the quantum degrees of freedom in these devices remains a challenge. Here, we experimentally implement a tunable heat sink that is potentially suitable for the initialization of superconducting qubits. Our device consists of two coupled resonators. The first resonator has a high quality factor and a fixed frequency whereas the second resonator is designed to have a low quality factor and a tunable resonance frequency. We engineer the low quality factor using an on-chip resistor and the frequency tunability using a superconducting quantum interference device. When the two resonators are in resonance, the photons in the high-quality resonator can be efficiently dissipated. We show that the corresponding loaded quality factor can be tuned from above 10 down to a few thousand at 10 GHz in good quantitative agreement with our theoretical model.
超导微波电路在诸如量子信息处理等实际量子技术应用中展现出巨大潜力。然而，在这些器件中对量子自由度进行快速且按需初始化仍然是一项挑战。在此，我们通过实验实现了一种潜在适用于超导量子比特初始化的可调谐热沉。我们的器件由两个耦合谐振器组成。第一个谐振器具有高品质因数和固定频率，而第二个谐振器被设计为具有低品质因数和可调谐谐振频率。我们利用片上电阻来设计低品质因数，并利用超导量子干涉器件来实现频率可调谐性。当两个谐振器发生共振时，高品质谐振器中的光子能够被高效耗散。我们表明，在10吉赫兹时，相应的加载品质因数能够从10以上调谐至几千，与我们的理论模型在定量上吻合良好。
