Superconducting gatemon qubit based on a proximitized two-dimensional electron gas
Superconducting gatemon qubit based on a proximitized two-dimensional electron gas
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DOI：
10.1038/s41565-018-0207-y
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发表时间：
2018-10-01
影响因子：
38.3
通讯作者：
Petersson, Karl D.
中科院分区：
文献类型：
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作者：
Casparis, Lucas;Connolly, Malcolm R.;Petersson, Karl D.
跨越约瑟夫森结（JJ）的库珀对的相干隧穿产生非线性电感，该非线性电感广泛用于基于超导电路的量子信息处理器中，从设置量子比特跃迁频率（1）和量子比特间耦合强度（2）到用于量子限制读出的参量放大器的增益（3）。电感可以通过调整单个JJ的金属氧化物尺寸来设置，也可以通过在具有局部电流偏置磁通线的超导量子干涉器件中并联多个JJ来进行磁调谐。基于超导体-半导体混合体的JJ代表了一种诱人的全电动替代品。门控子是最近开发的transmon变体，其采用局部门控纳米线超导体-半导体JJ用于量子位控制（4，5）。在这里，我们超越了概念验证，并证明了从晶圆级二维电子气（2DEG）蚀刻的半导体通道是构建可扩展的基于闸子的量子计算机的合适平台。我们通过执行电压控制的单量子比特旋转和双量子比特交换操作，证明了2DEG门振子满足要求（6）。我们测量量子位相干时间高达类似2 μ s，在2DEG基板的介电损耗的限制。
The coherent tunnelling of Cooper pairs across Josephson junctions (JJs) generates a nonlinear inductance that is used extensively in quantum information processors based on superconducting circuits, from setting qubit transition frequencies(1) and interqubit coupling strengths(2) to the gain of parametric amplifiers(3) for quantum-limited readout. The inductance is either set by tailoring the metal oxide dimensions of single JJs, or magnetically tuned by parallelizing multiple JJs in superconducting quantum interference devices with local current-biased flux lines. JJs based on superconductor-semiconductor hybrids represent a tantalizing all-electric alternative. The gatemon is a recently developed transmon variant that employs locally gated nanowire superconductor-semiconductor JJs for qubit controls(4,5). Here we go beyond proof-of-concept and demonstrate that semiconducting channels etched from a wafer-scale two-dimensional electron gas (2DEG) are a suitable platform for building a scalable gatemonbased quantum computer. We show that 2DEG gatemons meet the requirements(6) by performing voltage-controlled single qubit rotations and two-qubit swap operations. We measure qubit coherence times up to similar to 2 mu s, limited by dielectric loss in the 2DEG substrate.