拉曼耦合双量子比特系统中的多参数量子估计
Multiparameter Quantum Estimation in a Raman-Coupled Two-Qubit System
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中文总结 AI 辅助
研究拉曼耦合双量子比特系统的多参数量子估计，通过推导量子费希尔信息矩阵解析表达式，获得量子克拉美-罗界，揭示最佳工作区域，表明同时估计在特定区域优于独立估计，为该系统精度极限及量子传感等提供见解。
中文摘要 AI 辅助
我们研究了处于热平衡的拉曼耦合双量子比特系统中的多参数量子估计。推导了量子费希尔信息矩阵的解析表达式，以表征温度和拉曼耦合强度的同时估计。获得了相应的量子克拉美-罗界，并与单个估计策略的界进行了比较。结果揭示了由热涨落和相干相互作用之间的相互作用决定的最佳工作区域。特别是，量子测温显示出明确的最佳温度窗口，而拉曼耦合强度的估计在低温和弱耦合区域显著增强。我们进一步表明，在适当的参数区域内，同时估计可以优于独立估计，突出了多参数量子计量学的优势。这些结果为拉曼耦合双量子比特系统的最终精度极限提供了分析见解，并确定了量子传感和量子测温的有前景的工作区域。
英文摘要
We investigate multiparameter quantum estimation in a Raman-coupled two-qubit system at thermal equilibrium. Analytical expressions for the quantum Fisher information matrix are derived to characterize the simultaneous estimation of the temperature and Raman coupling strength. The corresponding quantum Cramér--Rao bounds are obtained and compared with those of individual estimation strategies. Our results reveal optimal operating regimes determined by the interplay between thermal fluctuations and coherent interactions. In particular, quantum thermometry exhibits a well-defined optimal temperature window, whereas the estimation of the Raman coupling strength is significantly enhanced in the low-temperature and weak-coupling regime. We further show that simultaneous estimation can outperform independent estimation within appropriate parameter regions, highlighting the advantages of multiparameter quantum metrology. These results provide analytical insights into the ultimate precision limits of Raman-coupled two-qubit systems and identify promising operating regimes for quantum sensing and quantum thermometry.
