Entanglement distribution over quantum code-division-multiple-access networks

TL;DR

This paper introduces a novel quantum entanglement distribution method over code-division-multiple-access networks using chaotic phase shifts, enabling multiple user pairs to share the same quantum channel effectively and robustly.

Contribution

The paper proposes a new encoding and decoding scheme using chaotic phase shifts for quantum networks, allowing multiple users to share quantum channels and generate entanglement more feasibly.

Findings

Maximally-entangled states can be generated between user pairs.

The method is robust against certain channel noises.

Implementation with bright coherent lights is more feasible than single-photon approaches.

Abstract

We present a method for quantum entanglement distribution over a so-called code-division-multiple-access network, in which two pairs of users share the same quantum channel to transmit information. The main idea of this method is to use different broad-band chaotic phase shifts, generated by electro-optic modulators (EOMs) and chaotic Colpitts circuits, to encode the information-bearing quantum signals coming from different users, and then recover the masked quantum signals at the receiver side by imposing opposite chaotic phase shifts. The chaotic phase shifts given to different pairs of users are almost uncorrelated due to the randomness of chaos and thus the quantum signals from different pair of users can be distinguished even when they are sent via the same quantum channel. It is shown that two maximally-entangled states can be generated between two pairs of users by our method mediated by bright coherent lights, which can be more easily implemented in experiments compared with single-photon lights. Our method is robust under the channel noises if only the decay rates of the information-bearing fields induced by the channel noises are not quite high. Our study opens up new perspectives for addressing and transmitting quantum information in future quantum networks.