Superconducting quantum bits<xref rid="cpb_27_2_027401fn1" ref-type="fn">*</xref> <fn id="cpb_27_2_027401fn1"> <label>*</label> <p>Project supported by the National Natural Science Foundation of China (Grant Nos. 91321208 and 11674380) and the National Key Basic Research Program of the Ministry of Science and Technology of China (Grant Nos. 2014CB921202, 2015CB921104, and 2016YFA0300601).</p> </fn>

Superconducting quantum bits* *

Project supported by the National Natural Science Foundation of China (Grant Nos. 91321208 and 11674380) and the National Key Basic Research Program of the Ministry of Science and Technology of China (Grant Nos. 2014CB921202, 2015CB921104, and 2016YFA0300601).

Liu Wei-Yang^{1, 2}, Zheng Dong-Ning^{1, 2}, Zhao Shi-Ping^{1, 2, †}

(color online) (a) Current-biased Josephson junction as a phase qubit and (b) its potential and energy levels. (c) and (d) Corresponding ones of the rf-SQUID-type phase qubit, which can also be operated as a flux qubit.