基于广义扭转动力学的qutrit系综中量子增强的单参数与多参数计量学
Quantum-enhanced single and multiparameter metrology in qutrit ensembles by generalized twisting dynamics
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中文总结 AI 辅助
本文提出三种单轴扭转模型的qutrit推广形式，用于qutrit系综的量子增强计量，可实现多方向近海森堡标度传感，能克服估计模糊性等问题，还利用su(3)代数实现对易生成元的近海森堡标度计量。
中文摘要 AI 辅助
原子系综的量子增强传感主要聚焦于基于qubit的协议，尽管越来越多的实验平台已具备对多能级系统进行相干控制和纠缠的能力。本文通过引入三种实验可行的单轴扭转（OAT）模型的qutrit推广形式，研究qutrit系综的量子增强传感，这些推广形式仅在两个能级间涉及纠缠操作，第三个能级主要作为旁观者。我们利用量子费信息工具箱表征动态生成态的计量学效用，数值发现所有三种模型在量子增强传感的编码方向上提供了相当大的自由度，在短演化时间后，8个可能方向中多达6个呈现接近海森堡标度的特性。我们讨论了通过有效时间反转协议获取这种增强计量精度的实验途径，此外，我们研究了估计模糊性和局域耗散的实际问题，表明通过优化传感器工作点可在很大程度上克服这些问题。最后，我们表明，随着系统规模增大，在零工作点下，同时估计不同方向编码的多个参数时的测量不相容性被抑制，在此过程中，我们发现其中一种模型可利用一对对易生成元实现接近海森堡标度的计量，这一可能性源于su(3)代数，因此在基于qubit系综的集体SU(2)旋转传感器中不存在该特性。
英文摘要
Quantum-enhanced sensing with atomic ensembles has predominantly focused on qubit-based protocols, despite the growing ability of many experimental platforms to coherently control and entangle multi-level systems. Here, we investigate quantum-enhanced sensing with qutrit ensembles by introducing three experimentally feasible qutrit generalisations of the one-axis twisting (OAT) model that involve entangling operations only between two levels, while the third level primarily acts as a spectator. We characterize the metrological utility of the dynamically generated states using the quantum Fisher information toolbox. We find numerically that all three models offer considerable freedom in encoding direction for quantum-enhanced sensing, with up to 6 out of 8 possible directions exhibit near-Heisenberg scaling after a short evolution time. We discuss experimental access to this enhanced metrological precision via effective time-reversal protocols. Furthermore, we examine the practical issues of estimation ambiguity and local dissipation, and show that they can be largely overcome by optimizing the sensor operating point. Finally, we show that the measurement incompatibility in estimating multiple parameters simultaneously encoded in different directions with near-Heisenberg scaling of precision is suppressed at the zero operating point as the system size increases. In the process, we find that one of the models enables near-Heisenberg scaling metrology with a pair of commuting generators, a possibility that arises from the $su(3)$ algebra and is thus absent in qubit-ensemble based sensors of collective $SU(2)$ rotations.
