Two-parameter estimation in a matter-wave Sagnac interferometer  

作　　者：Xu Yu Hong-Bin Liang Xiao-Guang Wang 

机构地区：[1]Zhejiang Institute of Modem Physics,Department of Physics,Zhejiang University,Hangzhou 310027,China [2]Graduate School of China Academy of Engineering Physics,Beijing 100193,China

出　　处：《Communications in Theoretical Physics》2020年第9期39-48,共10页理论物理通讯（英文版）

基　　金：National Key Research and Development Program of China(Grants No. 2017YFA0304202 and No. 2017YFA0205700);the NSFC (Grants No. 11 875 231 and No. 11 935 012);the Fundamental Research Funds for the Central Universities through Grant No. 2018FZA3005。

摘　　要：We explore the general characteristics of a matter-wave Sagnac interferometer in a two-parameter estimation scheme. We find that the measurement precisions of both parameters cannot reach the Heisenberg limit(HL) simultaneously when the input state is maximally entangled. Only one of the parameters' uncertainties can approach the HL while the other is scaled by the standard quantum limit.We provide the conditions with which the measurement precision of the specific parameter can reach the HL. We also discuss and figure out the concrete expressions of the constraint conditions for saturating the quantum Cramér–Rao bound. To satisfy these constraint conditions, the evolution time has to be a series of discrete values. Additionally, we calculate the variances of the parameters through some examples under these constraint conditions. The results provided in our work show some intrinsic features of the matter-wave Sagnac interferometer for the two-parameter estimation, which can be valuable in actual experiments.

关 键 词：multi-parameter estimation matter wave Sagnac interferometer Heisenberg limit 

分 类 号：O413[理学—理论物理]