Quantum interferometry via a coherent state mixed with a squeezed number state  

作　　者：Li-Li Hou Yong-Xing Sui Shuai Wang Xue-Fen Xu 侯丽丽;眭永兴;王帅;许雪芬(School of Mathematics and Physics Jiangsu University of Technology;Department of Fundamental Courses Wuxi Institute of Technology)

机构地区：[1]School of Mathematics and Physics Jiangsu University of Technology [2]Department of Fundamental Courses Wuxi Institute of Technology

出　　处：《Chinese Physics B》2019年第4期196-201,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.11404040);the Qing Lan Project of the Higher Educations of Jiangsu Province of China

摘　　要：We theoretically investigate the phase sensitivity with parity measurement on a Mach–Zehnder interferometer with a coherent state combined with a squeezed number state. Within a constraint on the total mean photon number, we find, via parity measurement, that the mixing of a coherent state and squeezed number state can give better phase sensitivity than mixing a coherent state and squeezed vacuum state when the phase shift deviates from the optimal phase φ= 0. In addition,we show that the classical Fisher information for parity measurement saturates the quantum Fisher information when the phase shift approaches to zero. Thus, the quantum Crame′r–Rao bound can be reached via the parity measurement in the case of φ= 0.We theoretically investigate the phase sensitivity with parity measurement on a Mach–Zehnder interferometer with a coherent state combined with a squeezed number state. Within a constraint on the total mean photon number, we find, via parity measurement, that the mixing of a coherent state and squeezed number state can give better phase sensitivity than mixing a coherent state and squeezed vacuum state when the phase shift deviates from the optimal phase φ= 0. In addition,we show that the classical Fisher information for parity measurement saturates the quantum Fisher information when the phase shift approaches to zero. Thus, the quantum Crame′r–Rao bound can be reached via the parity measurement in the case of φ= 0.

关 键 词：QUANTUM OPTICS phase sensitivity QUANTUM METROLOGY 

分 类 号：O4[理学—物理]