Parity-based estimation in an SU(1,1) interferometer with photon-subtracted squeezed vacuum states

• Published in: Optics communications 2023-06, Vol.537, p.129417, Article 129417
• Main Authors: Hou, Li-Li, Zhang, Jian-Dong, Wang, Shuai
• Format: Article
• Language: English
• Subjects: Non-Gaussian states; Parity detection; Quantum metrology; SU(1,1) interferometer
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2023.129417

We theoretically investigate the parity-based phase estimation and the quantum Fisher information in an SU(1,1) interferometer with different phase configuration. For the parity detection, we analytically demonstrate that the signal of the measurement will hold the same for arbitrary phase configurations within the constraint of the sum of the estimated phases occur in both arms of the interferometer. When the mixing a coherent state and a photon-subtracted squeezed vacuum state (PSSVS) as the input state, we further investigate the advantage of improving phase sensitivity for such input state. Our results indicate that both phase sensitivity and resolution with the PSSVS are superior to those with the squeezed vacuum state (SVS) for a given squeezing parameter. While within a constraint on the mean photon number of these squeezed states, the PSSVS does not improve the phase sensitivity at the optimal working point ϕ=0. However, when the phase shift slightly deviates from zero, the PSSVS still holds the advantage in phase sensitivity even under the condition of the same mean photon number. Finally, we obtain the quantum Fisher information of the PSSVS and compare it with the optimal phase sensitivity.