Quantum sensing of supersensitivity for the Ohmic quantum reservoir

作     者：Qing-Shou Tan Wei Wu Lan Xu Jing Liu Le-Man Kuang 

作者机构：Key Laboratory of Hunan Province on Information Photonics and Freespace Optical Communication College of Physics and Electronics Hunan Institute of Science and Technology Yueyang 414000 China Key Laboratory of Theoretical Physics of Gansu Province and Lanzhou Center for Theoretical Physics Lanzhou University Lanzhou 730000 China School of Physics and Chemistry Hunan First Normal University Changsha 410205 China MOE Key Laboratory of Fundamental Physical Quantities Measurement National Precise Gravity Measurement Facility School of Physics Huazhong University of Science and Technology Wuhan 430074 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China Synergetic Innovation Academy for Quantum Science and Technology Zhengzhou University of Light Industry Zhengzhou 450002 China 

出 版 物：《Physical Review A》 (Phys. Rev. A)

年 卷 期：2022年第106卷第3期

页      面：032602-032602页

核心收录：

基　　金：National Natural Science Foundation of China, NSFC, (11805047) Natural Science Foundation of Hunan Province, (11775075, 11935006, 1217050862, 12175075, 2022JJ30277) Science and Technology Program of Hunan Province, (2020RC4047) 

主　　题：Quantum metrology Quantum sensing Dynamical systems Hamiltonian systems Information theory 

摘      要：We propose an approach to implement a supersensitive estimation of the key parameters of the Ohmic-family spectral density with coherent spin states as the quantum sensor. This method can dramatically improve the estimation precision of the reservoir coupling strength as well as the cutoff frequency of the spectral density, by using both the number of spins N and encoding time t as effective resources. The quantum Fisher information indicates that the estimation sensitivity of the spectral density can surpass the shot-noise limit for all the sub-Ohmic, Ohmic, and super-Ohmic reservoirs. In particular, for super-Ohmic reservoirs, the precision can achieve a scaling ∝1/(Nt). We also present the measurement scheme which can saturate the quantum Cramér-Rao bound.