Contextuality in composite systems: the role of entanglement in the Kochen-Specker theorem

Place: Room 203, Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
Zoom link: https://us06web.zoom.us/j/84427806931?pwd=ODBjZkNCUW94VUhCREFxbjRSeDBFdz09
Meeting ID: 844 2780 6931
Access code: nisq

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Abstract: The fact that quantum theory radically departs from 'classical lines of thought' is a critical driver for its applications in quantum information and computation. A famous example of this radical departure---this nonclassicality---is entanglement. Bell's theorem shows that shared entanglement can be used to generate correlations between non-communicating parties in ways that are impossible to do without communication if one only had access to classical shared randomness. In their very formulation, both entanglement and Bell's theorem are composite notions of nonclassicality, i.e., they require at least two parties to be meaningful. Another key notion of nonclassicality is contextuality that follows from the Kochen-Specker theorem: this notion is applicable to single systems. I will present some recent results on the interplay between contextuality and entanglement in composite systems and their consequences for our understanding of restricted models of multiqubit quantum computation with state injection that have been previously proposed. Based on V.J. Wright and R. Kunjwal, Quantum 7, 900 (2023).