Maximally entangled states in pseudo-telepathy games

TL;DR

This paper investigates whether maximally entangled states can always be used to win pseudo-telepathy games with certainty, introducing weak projection games and linking the results to device-independent certification and communication complexity.

Contribution

It develops conditions where maximally entangled states suffice for winning certain pseudo-telepathy games and introduces weak projection games as a new class.

Findings

Maximally entangled states suffice for weak projection games.

Any pseudo-telepathy weak projection game certifies a maximally entangled state.

Constructs a class of games testing maximally entangled states of dimension Ω(n).

Abstract

A pseudo-telepathy game is a nonlocal game which can be won with probability one using some finite-dimensional quantum strategy but not using a classical one. Our central question is whether there exist two-party pseudo-telepathy games which cannot be won with probability one using a maximally entangled state. Towards answering this question, we develop conditions under which maximally entangled states suffice. In particular, we show that maximally entangled states suffice for weak projection games which we introduce as a relaxation of projection games. Our results also imply that any pseudo-telepathy weak projection game yields a device-independent certification of a maximally entangled state. In particular, by establishing connections to the setting of communication complexity, we exhibit a class of games $G_n$ for testing maximally entangled states of local dimension $\Omega(n)$. We leave the robustness of these self-tests as an open question.