Superconducting 'twin' qubit
Superconducting 'twin' qubit
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DOI：
10.1103/physrevb.102.115422
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发表时间：
2020-09-21
影响因子：
3.7
通讯作者：
Astafiev, O., V
中科院分区：
文献类型：
--
作者：
Antonov, I., V;Shaikhaidarov, R. S.;Astafiev, O., V
我们研究了一个由一对对称超导环路组成的通量量子位，每个环路中有两个约瑟夫森结，由一个共同的约瑟夫森结连接——一个“孪生”通量量子位。量子比特电容耦合到传输线，这使我们能够通过测量传播电磁波的散射来表征设备的频谱。我们对双环系统进行了详细的分析分析，揭示了其特性，并将实验结果与数值模拟结果进行了比较。在两个回路的半通量量子偏置下，量子位免受全局和局部磁场波动的影响，对二阶全局磁场的灵敏度要低得多。由于器件的对称性，系统选择规则允许奇偶跃迁，禁止在奇偶或奇偶电平之间跃迁。
We study a flux qubit consisting of a symmetrical pair of superconducting loops, with two Josephson junctions in each, joined by a common Josephson junction-a 'twin' flux qubit. The qubit is capacitively coupled to a transmission line, which allows us to characterize the spectrum of the device by measuring the scattering of propagated electromagnetic waves. We perform a detailed analytical analysis of the double-loop system, revealing its properties, and compare experimental results with numerical simulations. At half-flux quantum bias of both loops, the qubit is protected against global and local magnetic field fluctuations with much less sensitivity to the global field in the second order. The system selection rules allow even-odd transitions and prohibit transitions between even-even or odd-odd levels due to the symmetry of the device.