Experimental Quantum Advantage in the Odd-Cycle Game

TL;DR

This paper demonstrates the first experimental quantum advantage in the odd-cycle game by entangling two ions and achieving a winning probability significantly above classical limits, confirming quantum nonlocality.

Contribution

It presents the first experimental realization of the odd-cycle game showing quantum advantage with loophole-free implementation and high fidelity to the theoretical maximum.

Findings

Quantum strategy outperforms classical by ~26 sigma

Achieved 97.8% of the theoretical quantum winning probability

Measured a nonlocal content of 0.54, the largest for separate devices

Abstract

We report the first experimental demonstration of the odd-cycle game. We entangle two ions separated by ~2 m and the players use them to win the odd-cycle game with a probability ~26 sigma above that allowed by the best classical strategy. The experiment implements the optimal quantum strategy, is free of loopholes, and achieves 97.8(3) % of the theoretical limit to the quantum winning probability. We perform the associated Bell test and measure a nonlocal content of 0.54(2) -- the largest value for physically separate devices, free of the detection loophole, ever observed.