Surmounting intrinsic quantum-measurement uncertainties in Gaussian-state tomography with quadrature squeezing

TL;DR

This paper demonstrates that quadrature squeezing enhances quantum-estimation accuracy in Gaussian-state tomography, especially with heterodyne detection, by overcoming intrinsic measurement uncertainties and outperforming homodyne detection in certain scenarios.

Contribution

It analytically shows how quadrature squeezing improves heterodyne detection performance over homodyne detection in Gaussian-state tomography, revealing a fundamental relationship between measurement uncertainties.

Findings

Heterodyne detection can outperform homodyne detection with squeezing.

Quadrature squeezing reduces measurement uncertainties.

Heterodyne detection benefits from squeezing in Gaussian-state estimation.

Abstract

We reveal that quadrature squeezing can result in significantly better quantum-estimation performance with quantum heterodyne detection (of H. P. Yuen and J. H. Shapiro) as compared to quantum homodyne detection for Gaussian states, which touches an important aspect in the foundational understanding of these two schemes. Taking single-mode Gaussian states as examples, we show analytically that the competition between the errors incurred during tomogram processing in homodyne detection and the Arthurs-Kelly uncertainties arising from simultaneous incompatible quadrature measurements in heterodyne detection can often lead to the latter giving more accurate estimates. This observation is also partly a manifestation of a fundamental relationship between the respective data uncertainties for the two schemes. In this sense, quadrature squeezing can be used to overcome intrinsic quantum-measurement uncertainties in heterodyne detection.