Quantum Contextuality in Quantum Mechanics and Beyond

Samson Abramsky University of Oxford, UK Contextuality and quantum advantage One way of understanding contextuality and its consequences is to see how it can be used to gain advantage in information-processing tasks. We show how quantum resources can be used to gain advantage in games witnessing the fundamental logical and computational concept of homomorphism between relational structures. This has wide applications, to constraint satisfaction, graph invariants, and beyond. This form of quantum advantage is equivalent to finding state-independent quantum witnesses for strong contextuality, in the hierarchy of notions of contextuality defined by Abramsky and Brandenburger.