Experimental characterization of Gaussian quantum communication channels

TL;DR

This paper experimentally characterizes Gaussian quantum communication channels using shared entanglement, measuring their properties and assessing their capacity, fidelity, and security features in a continuous variable quantum teleportation setup.

Contribution

It provides a comprehensive experimental analysis of Gaussian quantum channels, including full covariance matrix measurement and capacity estimation, advancing practical quantum communication.

Findings

Determined lower bound to quantum channel capacity.

Measured teleportation fidelity of coherent states.

Achieved positive secret key rate for two channels.

Abstract

We present a full experimental characterization of continuous variable quantum communication channels established by shared entanglement together with local operations and classical communication. The resulting teleportation channel was fully characterized by measuring all elements of the covariance matrix of the shared two-mode squeezed Gaussian state. From the experimental data we determined the lower bound to the quantum channel capacity, the teleportation fidelity of coherent states and the logarithmic negativity and the purity of the shared state. Additionally, a positive secret key rate was obtained for two of the established channels.