Playing quantum nonlocal games with six noisy qubits on the cloud

TL;DR

This paper demonstrates quantum advantage in nonlocal games using six noisy qubits on cloud quantum computers by optimizing circuits and error mitigation, showing quantum advantage even in less accurate devices.

Contribution

It implements a minimal nonlocal game on cloud quantum computers with optimized techniques, achieving quantum advantage despite noise.

Findings

Quantum advantage observed on IBM, Ionq, Honeywell cloud devices.

Optimization techniques enable crossing classical thresholds.

Quantum advantage demonstrated in less accurate quantum computers.

Abstract

Nonlocal games are extensions of Bell inequalities, aimed at demonstrating quantum advantage. These games are well suited for noisy quantum computers because they only require the preparation of a shallow circuit, followed by the measurement of non-commuting observable. Here, we consider the minimal implementation of the nonlocal game proposed in Science 362, 308 (2018). We test this game by preparing a 6-qubit cluster state using quantum computers on the cloud by IBM, Ionq, and Honeywell. Our approach includes several levels of optimization, such as circuit identities and error mitigation and allows us to cross the classical threshold and demonstrate quantum advantage in one quantum computer. We conclude by introducing a different inequality that allows us to observe quantum advantage in less accurate quantum computers, at the expense of probing a larger number of circuits.