Unbalanced Homodyne Correlation Measurements

TL;DR

This paper presents a novel unbalanced homodyne correlation measurement method that efficiently measures high-order moments of quantum light states without photon-number resolution, enabling direct certification of quantum properties.

Contribution

It introduces a new measurement technique using a displaced dephased laser to access normal-ordered moments up to high orders, simplifying quantum state characterization.

Findings

Successfully measured moments of quantum states up to high orders.

Certified quantum properties of light directly through normal-ordered observables.

Demonstrated method on weakly squeezed vacuum and single-photon-added thermal state.

Abstract

A method is introduced which allows to measure normal-ordered moments of the displaced photon-number operator up to high orders. It is based on unbalanced homodyne correlation measurements, the local oscillator being replaced by a displaced dephased laser. The measured moments yield a simple approximation of the full quantum state, which is obtained without the need of photon-number resolution. Quantum properties of light are efficiently certified through the direct detection of normal-ordered observables, which is illustrated for a weakly squeezed vacuum and a single-photon-added thermal state.