Enhancing parameter precision of optimal quantum estimation by direct quantum feedback

TL;DR

This paper proposes using quantum feedback to improve the precision of quantum parameter estimation in dissipative qubits, showing increased quantum Fisher information and reduced decay over time.

Contribution

It introduces a novel quantum feedback method to enhance quantum Fisher information in dissipative systems, surpassing previous approaches.

Findings

Quantum feedback increases maximum quantum Fisher information.

Feedback reduces the decay rate of information over time.

Enhanced parameter estimation precision demonstrated through dynamics analysis.

Abstract

Various schemes have been proposed to overcome the drawback of the decoherence on quantum-enhanced parameter estimation. Here we suggest an alternative method, quantum feedback, to enhance the parameter precision of optimal quantum estimation of a dissipative qubit by investigating its dynamics of quantum Fisher information. We find that compared with the case without feedback, the quantum Fisher information of the dissipative qubit in the case of feedback has a large maximum value in time evolution and a smaller decay rate in the long time.