Superconductive Circuits

Xingyu Wei, Junliang Jiang, Wenqu Xu +8 more

We design and fabricate a compact superconducting qubit circuit made of nano-thick NbN film on a high-resistivity silicon substrate, carrying seven transmon qubits. By comparing with the conventional superconducting qubit circuits made of superconducting films with hundred-nanometer thickness, our superconducting qubit circuit has much smaller size in the readout circuit, whose resonator length is only about 1/20 of that in a conventional superconducting circuit. Transmons are measured and characterized in the frequency and time domains with different flux bias. The transition frequency f01 can be adjusted in the range of several GHz. The qubit circuits made of such nano-thick material with high kinetic inductance are promising in the integration of quantum circuits.

National Research Council

Alan M. Kadin, H. Kroemer

Preview. AC Properties and Superconducting Energy Gap. Magnetic Properties of Superconductors. Superconducting Materials and Thin--Film Technology. Josephson Devices. Superconducting Digital Circuits. Superconducting Radiation Detectors. Epilogue: Future Prospects for Superconducting Circuits. Bibliography. Appendices. Indexes.

Gleb Krylov, Tahereh Jabbari, Eby G. Friedman

Hirotaka Terai, Taro YAMASHITA, Shigehito Miki +2 more

The superconducting single-flux-quantum (SFQ) circuit is the ultimate energy-efficient digital circuit technology. The SFQ circuits are very promising for applications not only to huge systems such as supercomputers and/or high-end routers but also to the signal processing circuit operating with superconducting detectors. We introduce the recent progress in the SFQ circuit technology focusing on the application combined with superconducting single-photon detectors (SSPDs). The four-pixel SSPD array was successfully operated with the SFQ signal processing circuit in the 0.1 W Gifford McMahon refrigerator.

Thomas Y. Hsiang