AI 中文总结
本研究确定了多能级弛豫量子传感器在自适应控制下的极限信息率，证明其等于亮态平均布居寿命，并给出达到该极限的显式协议，同时表明独立监测即可实现最优渐近速率。
AI 中文摘要
我们确定了在无限制自适应控制下弛豫多能级量子传感器的极限信息率，并构造了一个能达到该极限的显式策略。我们考虑对弱场的传感，该弱场将基态与多个衰变回基态的激发态耦合，这一设置对于单个激发态可简化为振幅阻尼传感。我们证明，极限信息率恰好是由信号耦合到基态的亮态的平均布居寿命。尽管传感动力学通常涉及多个衰变模式，但一个显式的秩一协议——利用新鲜仪表和经典反馈监测基态-亮态相干性——能达到该速率，同时将其有限时间信息赤字保持在一个常数有界内。对于独立弛豫的相同传感器，独立的局部监测能达到它们各自最优速率之和，因此传感器间纠缠和联合量子纠错不能提高渐近速率。因此，自由布居衰减曲线为任意自适应控制下的最优传感性能提供了一个操作性度量。
英文摘要
We determine the ultimate information rate of a relaxing multilevel quantum sensor under unrestricted adaptive control and construct an explicit strategy that attains it. We consider sensing a weak field that couples the ground state to several excited states that decay back to the ground state, a setting that reduces to amplitude-damping sensing for a single excited state. We show that the ultimate information rate is exactly the mean population lifetime of the bright state coupled to the ground state by the signal. Although the sensing dynamics generally involve several decay modes, an explicit rank-one protocol that monitors the ground--bright coherence using fresh meters and classical feedback attains this rate while keeping its finite-time information deficit bounded by a constant. For independently relaxing identical sensors, independent local monitoring attains the sum of their individual optimal rates, so intersensor entanglement and joint quantum error correction cannot increase the asymptotic rate. Consequently, the free population-decay curve provides an operational measure of the optimal sensing performance under arbitrary adaptive control.
Comments6+10 pages, 2 figures
