Generation of high-fidelity four-photon cluster state and quantum-domain demonstration of one-way quantum computing

TL;DR

This paper reports the experimental generation of a high-fidelity four-photon cluster state and demonstrates its use in one-way quantum computing, confirming quantum advantage over classical methods.

Contribution

It presents a simple scheme for creating a four-photon cluster state with fidelity above 0.86 and demonstrates quantum operations surpassing classical bounds.

Findings

Fidelity of the generated state exceeds 0.86

State is distinguished from other four-qubit entanglements

Quantum operations outperform classical limits

Abstract

We experimentally demonstrate a simple scheme for generating a four-photon entangled cluster state with fidelity over 0.860 $\pm$ 0.015. We show that the fidelity is high enough to guarantee that the produced state is distinguished from Greenberger-Horne-Zeilinger, W, and Dicke types of genuine four-qubit entanglement. We also demonstrate basic operations of one-way quantum computing using the produced state and show that the output state fidelities surpass classical bounds, which indicates that the entanglement in the produced state essentially contributes to the quantum operation.