Entanglement distribution based on quantum walk in arbitrary quantum networks

TL;DR

This paper proposes a novel method for distributing high-dimensional entangled states across arbitrary quantum networks using quantum walks, with practical implementations and experimental validation on superconducting processors.

Contribution

It introduces modules for high-dimensional entanglement distribution via quantum walks and a scheme for arbitrary network distribution, including experimental demonstrations.

Findings

Quantum walk modules enable high-dimensional entanglement distribution.

Distribution scheme works on arbitrary quantum networks using Steiner trees.

Experimental validation achieved on superconducting quantum processors.

Abstract

In large-scale quantum networks, quantum repeaters provide an efficient method to distribute entangled states among selected nodes for realizing long-distance and complicated quantum communications. However, extending quantum repeater protocols to high-dimensional quantum states in existing experiments is not easy. Owing to the feasible physical implementations of quantum walks, we proposed various basic modules applicable to quantum repeaters for distributing high-dimensional entangled states via quantum walks, including $d$-dimensional Bell states and multi-particle $d$-dimensional GHZ states. Furthermore, based on the above schemes, we provided a high-dimensional entanglement distribution scheme for arbitrary quantum tree networks. By searching for a Steiner tree in a quantum network, we can achieve high-dimensional entanglement distributions over an arbitrary quantum network. We constructed a quantum fractal network based on $d$-dimensional GHZ states and analyzed the quantum transport properties of continuous quantum walks in the network. Compared with the continuous quantum walk on the Sierpinski gasket, the quantum walk on the new fractal network spreads more widely within the same time frame. Finally, we conducted five experiments to implement various basic modules of 2-party or 3-party entanglement distribution schemes in a superconducting quantum processor. Our study can serve as a building block for constructing large and complex quantum networks.