Quantum interferences reconstruction with low homodyne detection efficiency

TL;DR

This paper demonstrates through numerical experiments that quantum interferences can be reconstructed with homodyne detection efficiencies below 0.5, challenging standard thresholds and providing practical guidelines for low-efficiency quantum state tomography.

Contribution

It introduces a statistical approach enabling quantum interference measurement with efficiencies under 0.5, extending the capabilities of quantum state reconstruction.

Findings

Quantum interferences measurable below 0.5 efficiency

Numerical validation of alternative reconstruction techniques

Guidelines for low-efficiency homodyne tomography

Abstract

Standard quantum state reconstruction techniques indicate that a detection efficiency of $0.5$ is an absolute threshold below which quantum interferences cannot be measured. However, alternative statistical techniques suggest that this threshold can be overcome at the price of increasing the statistics used for the reconstruction. In the following we present numerical experiments proving that quantum interferences can be measured even with a detection efficiency smaller than $0.5$. At the same time we provide a guideline for handling the tomographic reconstruction of quantum states based on homodyne data collected by low efficiency detectors.