Improving phase estimation using number-conserving operations

Huan Zhang, Wei Ye, Chaoping Wei, Cunjin Liu, Zeyang Liao, and Liyun Hu
Phys. Rev. A 103, 052602 – Published 5 May 2021

Abstract

We propose a theoretical scheme to improve the resolution and precision of phase measurement with parity detection by using a nonclassical state generated by applying a number-conserving generalized superposition of products (GSP) operation, saa+taam with s2+t2=1, on a two-mode squeezed vacuum (TMSV) state as the input of Mach-Zehnder interferometer. Then, the statistical properties of the proposed GSP-TMSV are investigated via average photon number (APN), antibunching effect, and two-mode squeezing. Particularly, both higher order m GSP operation and lower proportion parameter s are beneficial for presenting larger total APN, which leads to the improvement of quantum Fisher information (QFI). In addition, we also compare the phase measurement precisions with and without photon losses between our scheme and the previous photon subtraction or photon addition schemes. It is found that our scheme, especially for the case of s=0, even in the presence of photon losses, has the best performance via the enhanced phase resolution, sensitivity, and QFI when compared to those previous schemes. Interestingly, without losses, the standard quantum-noise limit (SQL) is always broken through for our scheme and the phase uncertainty associated with the state of our scheme is closer to the corresponding Heisenberg limit (HL) than the TMSV in the larger total APN region, especially for the case of two-side GSP operation m,n1,1. However, in the presence of photon losses, the HL cannot be beaten, but the SQL can be broken through, particularly for the large total APN regimes.

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  • Received 16 December 2020
  • Revised 4 April 2021
  • Accepted 22 April 2021

DOI:https://doi.org/10.1103/PhysRevA.103.052602

©2021 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & TechnologyAtomic, Molecular & OpticalGeneral Physics

Authors & Affiliations

Huan Zhang1, Wei Ye1,2,*, Chaoping Wei3, Cunjin Liu1, Zeyang Liao4,†, and Liyun Hu1,‡

  • 1Center for Quantum Science and Technology, Jiangxi Normal University, Nanchang 330022, China
  • 2School of Computer Science and Engineering, Central South University, Changsha 410083, China
  • 3Key Laboratory of Water Information Cooperative Sensing and Intelligent Processing, Nanchang Institute of Technology, Nanchang 330022, China
  • 4School of Physics, Sun Yat-sen University, Guangzhou 510275, China

  • *yeweicsu@csu.edu.cn
  • liaozy7@mail.sysu.edu.cn
  • hlyun@jxnu.edu.cn

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Issue

Vol. 103, Iss. 5 — May 2021

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