Quantum Locality in Game Strategy

TL;DR

This paper demonstrates that in bipartite non-zero-sum games, local quantum correlations and separable states can outperform classical strategies, emphasizing the importance of quantum coherence without requiring entanglement or nonlocality.

Contribution

It shows that quantum advantage in game strategies can be achieved using only local quantum correlations and separable states, without entanglement or discord.

Findings

Separable states suffice for quantum advantage in certain games

Local quantum correlations outperform classical strategies

Proposed experiment with photon interferometry to demonstrate advantage

Abstract

Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players' input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage.