容错海森堡极限量子传感
Fault-Tolerant Heisenberg-Limited Quantum Sensing
中文总结 AI 辅助
该研究将容错量子计算理念引入量子传感，针对特定量子比特噪声模型，证明采用$N$量子比特重复码可在更长传感时间下实现海森堡标度，提升了量子传感的容错性能。
中文摘要 AI 辅助
量子传感器相比经典传感器在物理量测量中有望实现更高灵敏度，但量子传感优势的实现条件相当严苛，多数量子传感增强效果会在存在噪声、误差或系统校准不佳时消失。为克服这些局限，我们受容错量子计算理念启发将其引入量子传感领域。具体而言，我们考虑一种量子比特噪声模型，其中相位翻转错误概率随量子比特数指数级小于概率为$p$的比特翻转错误概率。针对该噪声结构，我们证明对于总传感时间$T$，$N$量子比特重复码在$T \backsim 1/p^{(N+1)/2}$时可实现海森堡标度，而不采用容错传感协议时$T \backsim 1/p$。
英文摘要
Quantum sensors hold great promise for achieving better sensitivity in the measurement of physical quantities compared to their classical counterparts. However, the conditions under which quantum advantage in sensing can be achieved are rather restrictive, and most quantum enhancements in sensing are lost in the presence of noise, errors, or a poorly calibrated system. To overcome these limitations, we are motivated to import ideas from fault-tolerant quantum computing to quantum sensing. Specifically, we consider a qubit noise model where the probability of phase-flip errors is exponentially smaller (in qubit number) compared to the probability of bit-flip errors that occur with probability $p$. For this noise structure, we demonstrate that, given a total sensing time $T$, Heisenberg scaling can be attained for times up to $T\propto 1/p^{(N+1)/2}$ for a $N$-qubit repetition code, in contrast with $T\propto 1/p$ without using a fault-tolerant sensing protocol.
