Towards Einstein-Podolsky-Rosen quantum channel multiplexing

TL;DR

This paper demonstrates the experimental implementation of quantum channel multiplexing using a broadband squeezed field, enabling multiple EPR entangled channels for quantum communication tasks like key distribution and teleportation.

Contribution

It introduces techniques for multiplexing multiple quantum channels via frequency modes from a single broadband squeezed field, advancing quantum communication capabilities.

Findings

Successfully implemented N=1 multiplexing with two squeezed states

Demonstrated techniques applicable for N>1 multiplexing

Showed potential for optimizing quantum information tasks

Abstract

A single broadband squeezed field constitutes a quantum communication resource that is sufficient for the realization of a large number N of quantum channels based on distributed Einstein-Podolsky-Rosen (EPR) entangled states. Each channel can serve as a resource for, e.g. independent quantum key distribution or teleportation protocols. N-fold channel multiplexing can be realized by accessing 2N squeezed modes at different Fourier frequencies. We report on the experimental implementation of the N=1 case through the interference of two squeezed states, extracted from a single broadband squeezed field, and demonstrate all techniques required for multiplexing (N>1). Quantum channel frequency multiplexing can be used to optimize the exploitation of a broadband squeezed field in a quantum information task. For instance, it is useful if the bandwidth of the squeezed field is larger than the bandwidth of the homodyne detectors. This is currently a typical situation in many experiments with squeezed and two-mode squeezed entangled light.