发表机构
The University of British Columbia; Stewart Blusson Quantum Matter Institute, University of British Columbia; Delft University of Technology; QuTech and Kavli Institute of Nanoscience, Delft University of Technology; Department of Physics and Astronomy, University of British Columbia（不列颠哥伦比亚大学; 不列颠哥伦比亚大学斯图尔特·布拉森量子物质研究所; 代尔夫特理工大学; 代尔夫特理工大学QuTech与卡弗里纳米科学研究所; 不列颠哥伦比亚大学物理与天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种基于栅极色散检测的紧凑读出方法，用于Ge/SiGe异质结构量子点，通过单空穴盒增强信噪比，实现快速电荷读出。
AI 中文摘要
自旋量子比特是可扩展量子信息处理的一个有吸引力的平台，最近，Ge异质结构中的横向栅极量子点（QDs）已成为自旋量子比特的主要实现方式。迄今为止，射频单空穴晶体管（SHT）和集成超导谐振器已被用于自旋和电荷读出，但其尺寸可能带来挑战。在这里，我们展示了Ge双量子点（DQD）以及单空穴盒（SHB）-DQD系统的紧凑型射频栅极色散电荷读出。我们通过这两种技术分辨了量子点装载和量子点间跃迁。我们发现，对于耦合强度$t_c \approx 5$ GHz的DQD，SHB将我们540 MHz电路的点间信噪比（SNR）提高了20倍，在135微秒时提供单位信噪比，而直接检测则需要2.7毫秒。功率和温度相关的测量表明，SNR受到介电损耗的限制，这损害了阻抗匹配。这些结果建立了一种基于栅极色散检测的紧凑读出方法，适用于Ge/SiGe异质结构量子点。
英文摘要
Spin qubits are an attractive platform for scalable quantum information processing, and recently, laterally gated quantum dots (QDs) in Ge heterostructures have emerged as a leading implementation of spin qubits. To date, RF single-hole transistors (SHT) and integrated superconducting resonators have been used for spin and charge readout, but their size can pose challenges. Here we demonstrate compact RF gate-dispersive charge readout of a Ge double QD (DQD), and a single hole box (SHB)-DQD system. We resolve QD loading and interdot transitions with both techniques. We find that the SHB enhances the interdot signal-to-noise ratio (SNR) of our 540 MHz circuit by a factor of 20 for a DQD coupling $t_c \approx 5$ GHz, providing a unity-SNR at 135 microseconds, c.f. for 2.7 miliseconds for the direct detection. Power- and temperature-dependent measurements verify that SNR is limited by dielectric loss which compromises impedance matching. These results establish a compact readout approach based on gate-dispersive detection for Ge/SiGe heterostructure QDs.
Comments6 pages, 4 figures and additional appendix
