arXiv:2512.24894cond-mat.mes-hallcs.CV2025-12

通过实时监测量子点阵列电荷跃迁线,实现自主校准与噪声分析。

Towards autonomous time-calibration of large quantum-dot devices: Detection, real-time feedback, and noise spectroscopy

  • 利用电荷跃迁图网络追踪电压漂移,实现自动补偿。
  • 在10量子点器件上实现稳定运行并解析噪声谱密度。
  • 适合大规模量子点处理器的自适应校准与故障诊断。

半导体量子点(QD)量子比特的性能和可扩展性受限于静电漂移和电荷噪声,这些因素会移动工作点并破坏量子比特参数。随着系统扩展到大型一维和二维阵列,手动重校准变得不切实际,亟需自主稳定框架。本文提出一种方法,利用重复获取的双量子点电荷稳定性图(CSDs)中完整的电荷跃迁线网络,作为局部静电环境的多维探测器。通过精确追踪特定跃迁随时间的运动,可检测电压漂移、识别突发电荷重构,并施加补偿更新以维持稳定工作条件。我们在10量子点器件上验证了该方法,实现了稳健的稳定化与实时诊断,可获取各量子点特异性噪声过程。高频射频反射测量的高采集率还支持时域噪声谱分析,能提取噪声功率谱密度,识别两能级涨落器,并分析阵列中的空间噪声关联。分析表明,100~μHz背景噪声主要由1/f²幂律漂移主导,伴有少数显著的两能级涨落器,设备中平均线性相关长度为(188±38) nm。这些能力构成了基于量子点的量子处理器可扩展、自主校准与表征模块的基础,为长时间、高保真度量子比特操作提供关键反馈。

原文摘要 · Abstract (English)

The performance and scalability of semiconductor quantum-dot (QD) qubits are limited by electrostatic drift and charge noise that shift operating points and destabilize qubit parameters. As systems expand to large one- and two-dimensional arrays, manual recalibration becomes impractical, creating a need for autonomous stabilization frameworks. Here, we introduce a method that uses the full network of charge-transition lines in repeatedly acquired double-quantum-dot charge stability diagrams (CSDs) as a multidimensional probe of the local electrostatic environment. By accurately tracking the motion of selected transitions in time, we detect voltage drifts, identify abrupt charge reconfigurations, and apply compensating updates to maintain stable operating conditions. We demonstrate our approach on a 10-QD device, showing robust stabilization and real-time diagnostic access to dot-specific noise processes. The high acquisition rate of radio-frequency reflectometry CSD measurements also enables time-domain noise spectroscopy, allowing the extraction of noise power spectral densities, the identification of two-level fluctuators, and the analysis of spatial noise correlations across the array. From our analysis, we find that the background noise at 100~$μ$\si{\hertz} is dominated by drift with a power law of $1/f^2$, accompanied by a few dominant two-level fluctuators and an average linear correlation length of $(188 \pm 38)$~\si{\nano\meter} in the device. These capabilities form the basis of a scalable, autonomous calibration and characterization module for QD-based quantum processors, providing essential feedback for long-duration, high-fidelity qubit operations.

量子点自主校准噪声谱量子计算

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