Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 41: Quantum information: Concepts and methods III
Q 41.1: Gruppenbericht
Mittwoch, 20. März 2013, 14:00–14:30, E 214
Quantum contextuality: state-independent inequalities, dimension witnesses, and challenges for new experiments — •Matthias Kleinmann1, Jochen Szangolies1, Costantino Budroni1, Otfried Gühne1, Adán Cabello2, and Jan-Åke Larsson3 — 1Universität Siegen, D-57068 Siegen, Germany — 2Universidad de Sevilla, E-41012 Sevilla, Spain — 3Linköpings Universitet, SE-58183 Linköping, Sweden
Quantum mechanics cannot be explained by a non-contextual classical theory. This fact was pioneered by Kochen and Specker and is one of the fundamental features of quantum measurements. In a non-contextual classical theory, the outcome of a measurement must be independent of the measurement context, i.e., independent of any other measurements that are performed along with it. But quantum mechanics does not obey this rule, as can be shown by the violation of a non-contextuality inequality. Such inequalities are a natural generalization of Bell inequalities and in particular it is possible to find non-contextuality inequalities that are violated for any quantum state, even the completely mixed state. In this talk, recent results will be summarized, in particular the construction of the most fundamental state-independent inequality and the dimension-dependence of the violation of a non-contextuality inequality. Despite quantum contextuality has been demonstrated in several experiments, many questions and challenges remain open and shall also be outlined in this talk.