利用绝热切变调制脉冲逼近单次量子比特频率跟踪的基本极限

中文摘要 AI 辅助

理解并抑制两能级量子系统中的噪声，对实现高保真度量子比特控制至关重要。传统频率跟踪技术（如Ramsey干涉测量法）存在灵敏度、带宽与动态范围之间的固有权衡限制。本文提出绝热切变调制（Adiabatic Tangentially-Modulated, ATM）脉冲，该脉冲基于量子绝热理论推导而来，可将量子比特失谐映射为S型近二元响应。通过数值模拟结合解析建模，我们表明脉冲灵敏度与失谐范围可通过简单设计参数独立调控；推导了支配这些量的标度关系，并验证其与模拟结果相符。单次ATM测量的灵敏度可与多次Ramsey平均所得灵敏度相媲美，能以更低的闭环白噪声基底跟踪更高频率的噪声分量。此外，与基于Shinnar-Le Roux形式主义的二元响应脉冲相比，该脉冲对振幅波动具有更强的鲁棒性。综上，这些特性确立了ATM脉冲作为鲁棒量子比特频率跟踪的极具潜力的方案。

英文摘要

Understanding and mitigating noise in two-level quantum systems is essential for achieving high-fidelity qubit control. Conventional frequency tracking techniques, such as Ramsey interferometry, are fundamentally limited by trade-offs between sensitivity, bandwidth, and dynamic range. Here we introduce the adiabatic tangentially-modulated (ATM) pulse, a pulse derived from quantum adiabatic theory that maps qubit detuning onto a sigmoidal, near-binary response. Using numerical simulations supported by analytical modeling, we show that pulse sensitivity and detuning range can be independently engineered through simple design parameters. We derive scaling relations governing these quantities and demonstrate their agreement with simulation. A single-shot ATM measurement achieves sensitivity comparable to that obtained from multi-shot Ramsey averaging, enabling tracking of substantially higher frequency noise components with a lower closed-loop white-noise floor. In addition, this pulse exhibits strong robustness to amplitude fluctuations compared with binary response pulses derived from the Shinnar-Le Roux formalism. Together, these properties establish the ATM pulse as a promising approach for robust qubit frequency tracking.

发表机构

• The University of New South Wales（新南威尔士大学）
• Diraq Pty Ltd（Diraq有限公司）

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