Data processing over single-port homodyne detection to realize super-resolution and super-sensitivity

TL;DR

This paper introduces a novel data-processing method for single-port homodyne detection in squeezed-state interferometry, enhancing phase resolution and sensitivity for super-resolution and super-sensitivity in quantum measurements.

Contribution

It proposes dividing measurement quadrature into three bins for improved phase measurement and develops a phase-estimation protocol that saturates the Cramer-Rao bound.

Findings

Enhanced phase resolution and sensitivity demonstrated.

The new estimator saturates the Cramer-Rao lower bound.

Method is effective under realistic experimental conditions.

Abstract

Performing homodyne detection at one port of squeezed-state light interferometer and then binarzing measurement data are important to achieve super-resolving and super-sensitive phase measurements. Here we propose a new data-processing technique by dividing the measurement quadrature into three bins (equivalent to a multi-outcome measurement), which leads to a higher improvement in the phase resolution and the phase sensitivity under realistic experimental condition. Furthermore, we develop a new phase-estimation protocol based on a combination of the inversion estimators of each outcome and show that the estimator can saturate the Cramer-Rao lower bound, similar to asymptotically unbiased maximum likelihood estimator.