Non-Markovian effect on quantum optical metrology under a dissipative environment

Abstract

Quantum metrology utilizes quantum effects to reach higher precision measurements of physical quantities compared with their classical counterparts. However the ubiquitous decoherence obstructs its application. Recently, non-Markovian effects are shown to be effective in performing quantum optical metrology under locally dissipative environments [PhysRevLett.123.040402 (2019)]. However, the mechanism is still rather hazy. Here, we uncover the reason why forming a bound state can protect the quantumness against a dissipative ambient via the quantum Fisher information of entangled coherent states. An exact analytical expression of the quantum Fisher information in the long-encoding-time condition is derived, which reveals that the dynamics of precision can asymptotically reach the ideal-case-promised one easily when the average photon number is small. Meanwhile, the scaling exhibits a transition from the weak Heisenberg limit to the subclassical limit with increasing of average photon number. Our work provides a recipe to realize ultrasensitive measurements in the presence of noise by utilizing non-Markovian effects.

Individual versus simultaneous estimation of two parameters in a correlated noisy environment

“…It is commonly believed that Markovian type environments have been proven to be harmful to quantum metrology due to the decay of QFI [8][9][10][11]. In contrast, non-Markovian type environments owing to memory effect which leads to revivals of QFI can guarantee the advantage of quantum metrological strategies [12][13][14][15][16]. It would be of great interest in engineering adverse environment to improve the accuracy of parameter estimation.…”