发表机构
Niels Bohr Institute, University of Copenhagen; School of Physics and Zhejiang Key Laboratory of Micro-nano Quantum Chips and Quantum Control, Zhejiang University; Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所; 浙江大学物理学院及微纳量子芯片与量子控制浙江省重点实验室; 哥本哈根大学尼尔斯·玻尔研究所尼尔斯·玻尔国际学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出双场传感器，通过联合测量原始信号与系统副本，饱和量子Fisher信息界，在多种实现中利用光子计数或零差探测达到量子极限，并扩展至多参数联合感知。
AI 中文摘要
连续测量在量子实验中扮演着基础性角色，然而，理解并提取连续探针信号中最大可能的信息仍然是一个重大挑战。在本工作中，我们证明，对于一大类传感器，通过将原始传感器信号与一个合适的系统副本进行联合测量，可以饱和量子Fisher信息界。我们阐明了这种双场传感器（TFS）的物理机制，并研究了其在从两能级原子到混合量子拉比模型等多种实现中的性能。在所有这些情形中，我们发现简单的光子计数或零差探测即可饱和理论量子极限。我们进一步证明，TFS在由量子Fisher信息矩阵量化的联合感知参数对方面达到了量子极限。
英文摘要
Continuous measurements play a fundamental role in quantum experiments, yet understanding and extracting the maximal possible information in a continuous probe signal remains a significant challenge. In this work, we show that for a wide class of sensors, the quantum Fisher information bound can be saturated through a combined measurement of signals from the original sensor and a suitable system copy. We elucidate the physical mechanism of such a twin-field sensor (TFS) and study its performance across diverse implementations, ranging from two-level atoms to a hybrid quantum Rabi model. In all of these cases, we find that simple photon counting or homodyne detection saturates the theoretical quantum limit. We further prove that the TFS achieves the quantum limits for the joint sensing of pairs of parameters as quantified by the quantum Fisher information matrix.
Comments8 pages, 4 figures
