Mancinska: Unbounded entanglement can be needed to achieve the optimal success probability
Laura Mancinska, Centre for Quantum Technologies, Singapore
Quantum entanglement is known to provide a strong advantage in many two-party distributed tasks. We investigate the question of how much entanglement is needed to reach optimal performance. For the first time we show that there exists a purely classical scenario for which no finite amount of entanglement suffices. To this end we introduce a simple two-party nonlocal game $H$, inspired by Hardy's paradox. In our game each player has only two possible questions and can provide bit strings of any finite length as answer.