Experimental Demonstration of Squeezed State Quantum Averaging

TL;DR

This paper experimentally demonstrates a quantum averaging process that uses harmonic mean to stabilize squeezed light sources, outperforming traditional methods, and applicable to various noise characteristics in quantum optics.

Contribution

It introduces and experimentally verifies a universal quantum averaging protocol based on harmonic mean, enhancing stabilization of quantum light sources.

Findings

Harmonic mean quantum averaging outperforms arithmetic mean in stabilizing squeezed light.

The protocol works for both uncorrelated and correlated noise sources.

Experimental results show improved variance stabilization in quantum optics applications.

Abstract

We propose and experimentally demonstrate a universal quantum averaging process implementing the harmonic mean of quadrature variances. The harmonic mean protocol can be used to efficiently stabilize a set of fragile squeezed light sources with statistically fluctuating noise levels. The averaged variances are prepared probabilistically by means of linear optical interference and measurement induced conditioning. We verify that the implemented harmonic mean outperforms the standard arithmetic mean strategy. The effect of quantum averaging is experimentally tested both for uncorrelated and partially correlated noise sources with sub-Poissonian shot noise or super-Poissonian shot noise characteristics.