Tolerance-enhanced SU(1,1) interferometers using asymmetric gain  

作　　者：张建东 王帅 Jian-Dong Zhang;Shuai Wang(School of Mathematics and Physics,Jiangsu University of Technology,Changzhou 213001,China)

机构地区：[1]School of Mathematics and Physics,Jiangsu University of Technology,Changzhou 213001,China

出　　处：《Chinese Physics B》2023年第1期190-195,共6页中国物理B（英文版）

基　　金：Project supported by Leading Innovative Talents in Changzhou (Grant No.CQ20210107);Shuangchuang Ph.D Award (Grant No.JSSCBS20210915);Natural Science Research of Jiangsu Higher Education Institutions of China (Grant No.21KJB140007);the National Natural Science Foundation of China (Grant No.12104193)。

摘　　要：SU(1,1) interferometers play an important role in quantum metrology. Previous studies focus on various inputs and detection strategies with symmetric gain. In this paper, we analyze a modified SU(1,1) interferometer using asymmetric gain. Two vacuum states are used as the input and on–off detection is performed at the output. In a lossless scenario,symmetric gain is the optimal selection and the corresponding phase sensitivity can achieve the Heisenberg limit as well as the quantum Cramer–Rao bound. In addition, we analyze the phase sensitivity with symmetric gain in the lossy scenario.The phase sensitivity is sensitive to internal losses but extremely robust against external losses. We address the optimal asymmetric gain and the results suggest that this method can improve the tolerance to internal losses. Our work may contribute to the practical development of quantum metrology.

关 键 词：SU(1 1)interferometer asymmetric gain Heisenberg limit quantum Cramer–Rao bound 

分 类 号：TH744.3[机械工程—光学工程]