Experimental Quantum Advantage in the Odd-Cycle Game

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.