On the power of multipartite entanglement for pseudotelepathy

TL;DR

This paper explores how multipartite entanglement enhances pseudotelepathy in quantum games, demonstrating that tripartite entanglement can outperform bipartite resources, including nonsignalling ones, in certain five-player scenarios.

Contribution

It introduces a five-player game that tripartite entanglement can win but bipartite nonsignalling resources cannot, highlighting the unique power of multipartite entanglement.

Findings

Tripartite entanglement enables winning certain pseudotelepathy games.

Bipartite nonsignalling resources cannot win the introduced five-player game.

Tripartite entanglement surpasses bipartite resources in specific quantum tasks.

Abstract

As early as 1935, Schr\"odinger recognized entanglement as ``not one but rather the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought''. Indeed, most remarkable phenomena in quantum information science, such as quantum computing and quantum teleportation, spring from clever uses of entanglement. Among them, pseudotelepathy enables two or more players to win systematically at some cooperative games with no need for communication between them, a restriction that would make the task impossible in a classical world. We investigate the power of multipartite entanglement for pseudotelepathy. Some known games that can be won with tripartite entanglement cannot be won with bipartite entanglement, but they can be won with bipartite nonsignalling resources such as the so-called Popescu--Rohrlich nonlocal box. We exhibit a five-player game that can be won with tripartite entanglement, but not with arbitrary bipartite nonsignalling resources even in the presence of arbitrary five-partite classical resources. This illustrates both the power of bipartite nonsignalling resources (over bipartite entanglement) and the even superior power of tripartite entanglement.