Quantum estimation for improving optomechanical coupling strength

Abstract

Enhanced quantum metrology is of vital importance for revealing the distinct features of quantum phenomena. Here we propose an effective scheme to significantly improve the quantum estimation of optomechanical coupling strength (OCS) with the assistance of two-level atoms, coherent feedback loop, and squeezed vacuum injection. Our results indicate that, by selecting appropriate atomic, quantum feedback and squeezing parameters, the estimation error of the OCS parameter can be greatly reduced. We explain the physical mechanisms behind these factors enhancing estimation precision of OCS parameter and explore the ideal parameter regions for estimating it. More importantly, the estimation precision obtained by our scheme exhibits stronger robustness against mechanical damping and ambient temperature in comparison with the unassisted case. In addition, we evaluate the performance of heterodyne detection, indicating that the measurement precision obtained through this method can approach the estimation precision obtained by our scheme. Further, the experimental feasibility of our scheme is discussed. The proposed scheme for enhancing quantum sensing is quite general and can also be applied to high-precision estimation of other physical parameters.