Robust Adaptive Quantum Phase Estimation

TL;DR

This paper demonstrates that incorporating robustness into quantum phase estimation significantly improves accuracy when dealing with uncertainties in system parameters, especially in quantum optical systems.

Contribution

It introduces a robust fixed-interval smoother for quantum phase estimation that explicitly accounts for parameter uncertainties, enhancing estimation performance.

Findings

Robust smoother improves phase estimation accuracy under uncertainties.

Explicit modeling of uncertainties enhances quantum measurement reliability.

Method applicable to quantum optical systems with phase noise.

Abstract

Quantum parameter estimation is central to many fields such as quantum computation, communications and metrology. Optimal estimation theory has been instrumental in achieving the best accuracy in quantum parameter estimation, which is possible when we have very precise knowledge of and control over the model. However, uncertainties in key parameters underlying the system are unavoidable and may impact the quality of the estimate. We show here how quantum optical phase estimation of a squeezed state of light exhibits improvement when using a robust fixed-interval smoother designed with uncertainties explicitly introduced in parameters underlying the phase noise.