Phase Diffusion in Low-EJ Josephson Junctions at Milli-Kelvin Temperatures
Phase Diffusion in Low-EJ Josephson Junctions at Milli-Kelvin Temperatures
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DOI：
10.3390/electronics12020416
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发表时间：
2023-01-01
期刊：
影响因子：
2.9
通讯作者：
Gershenson, Michael E.
中科院分区：
文献类型：
--
作者：
Lu, Wen-Sen;Kalashnikov, Konstantin;Gershenson, Michael E.
约瑟夫森能量E-J小于或接近1k的约瑟夫森结（Josephson junction, JJs）作为非线性元件广泛应用于在毫开尔文温度下运行的量子计算超导电路中。在电荷能E-C （E-J/E-C >> 1）较小的量子比特中，如transmon，随着E-J的减小，非相干相位滑移（IPS）可能成为主要的耗散源。本文报道了在毫开尔文温度下，对低e - j晶体的IPS进行了系统的研究。当E-J低于1 K时，观察到IPS对临界（开关）电流的强烈抑制和零偏置电阻的快速增长。随着超导量子比特相干性的进一步提高，ips诱导的耗散可能会限制基于低e - j结的量子比特的性能。这些结果为未来这种量子比特的改进指明了方向。
Josephson junctions (JJs) with Josephson energy E-J less than or similar to 1 K are widely employed as non-linear elements in superconducting circuits for quantum computing operating at milli-Kelvin temperatures. In the qubits with small charging energy E-C ( E-J/E-C >> 1 ), such as the transmon, the incoherent phase slips (IPS) might become the dominant source of dissipation with decreasing E-J. In this work, a systematic study of the IPS in low-E-J JJs at milli-Kelvin temperatures is reported. Strong suppression of the critical (switching) current and a very rapid growth of the zero-bias resistance due to the IPS are observed with decreasing E-J below 1 K. With further improvement of coherence of superconducting qubits, the observed IPS-induced dissipation might limit the performance of qubits based on low-E-J junctions. These results point the way to future improvements of such qubits.