InAs-Pb四端器件中20秒的奇偶寿命
20 Second Parity Lifetime in an InAs--Pb Tetron Device
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中文总结 AI 辅助
通过用高能隙超导体铅替代铝，在InAs-Pb四端器件中实现了约20秒的奇偶寿命，验证了拓扑量子计算中能隙增大可显著提升器件性能的原理。
中文摘要 AI 辅助
拓扑量子计算的一个核心承诺是，增大激发能隙可以显著提升器件性能。在这里，我们通过干涉测量单次奇偶测量，在InAs-Pb四端器件中实验验证了这一原理。通过在我们的超导体-半导体混合器件中用更高能隙的超导体铅替代铝，我们提高了拓扑相的鲁棒性。此外，为了实现快速且精确的大规模调试，我们开发了一种射频测量技术，该技术能够分辨低能线端态，并直接测量其能量分裂，精度达到μeV。我们利用该技术在一个多四端阵列中调试一个器件，并对其中一个四端的混合纳米线进行奇偶测量。通过可控地切换纳米线奇偶性，我们观察到在干涉环中与混合纳米线耦合的量子点的量子电容出现h/2e周期的双峰偏移。进一步的时间分辨测量显示，特征奇偶切换时间约为20秒，某些实例达到分钟量级。如此长的奇偶寿命比典型的量子比特操作时间（微秒量级）长数个数量级。最后，我们讨论了这对泡利测量保真度的潜在影响。
英文摘要
A central promise of topological quantum computing is that increasing the excitation gap improves device performance significantly. Here, we experimentally validate this principle in an InAs--Pb tetron device via interferometric single-shot parity measurements. By replacing aluminum with the higher-gap superconductor lead in our superconductor-semiconductor hybrid devices, we have improved the robustness of our topological phase. In addition, to enable fast and precise bring-up at scale, we have developed an rf measurement technique that resolves low-energy wire-end states and directly measures their energy splitting with $μ\text{eV}$ precision. We employ this technique to bring up a device in a multi-tetron array and perform parity measurements of one of the tetron's hybrid nanowires (NWs). By controllably switching the wire parity, we observe $h/2e$-periodic bimodal shifts in the quantum capacitance of a quantum dot coupled to the hybrid nanowire in an interference loop. Further time-resolved measurements reveal a characteristic parity switching time of $\sim 20$ s with some instances reaching minute-scale. Such extremely long parity lifetimes are orders of magnitude longer than typical qubit operation times, which are on the order of $μ\text{s}$. Finally, we discuss potential implications for the fidelity of Pauli measurements.
