Improving Parameters Precision of Quantum Estimation by Homodyne-Based Feedback Control

Abstract

In this paper, we investigate the improvement of quantum Fisher information (QFI) of a single-qubit system coupled to a common reservoir by homodyne-based feedback control. It is shown that by controlling the polar parameter of the initial quantum state, one may improve the quantum Fisher information of the estimated parameters. By comparing the effects of different feedback control types on QFI, we find that under the homodyne-based feedback control, when the feedback Hamiltonian is selected as λσx, the estimation precision of feedback parameters and dissipation coefficient can be improved.