title: Temporal quantum correlations and Leggett-Garg inequalities in multilevel systems.
abstract: We show that the quantum bound for temporal correlations in a Leggett-Garg test, analogous to the Tsirelson bound for spatial correlations in a Bell test, strongly depends on the number of levels N that can be accessed by the measurement apparatus via projective measurements. We provide exact bounds for small N that exceed the known bound for the Leggett-Garg inequality, and we show that in the limit N→∞ the Leggett-Garg inequality can be violated up to its algebraic maximum.
authors.affiliation: Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Strasse 3, D-57068 Siegen, Germany.
authors.forename: Costantino
authors.initials: C
authors.lastname: Budroni
authors.affiliation: Department of Physics and Mathematics, University of Hull, Kingston-upon-Hull HU6 7RX, United Kingdom.
authors.forename: Clive
authors.initials: C
authors.lastname: Emary