Regensburg 2022 – wissenschaftliches Programm

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QI: Fachverband Quanteninformation

QI 14: Quantum Foundations

QI 14.1: Hauptvortrag

Freitag, 9. September 2022, 09:30–10:00, H9

Testing quantum theory with generalized noncontextuality — •Markus P. Müller^{1, 2, 3} and Andrew J. P. Garner¹ — ¹Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria — ²Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria — ³Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5, Canada

It is a fundamental prediction of quantum theory that states of physical systems are described by complex vectors or density operators on a Hilbert space. However, many experiments admit effective descriptions in terms of other state spaces, such as classical probability distributions or quantum systems with superselection rules. Here, we ask which probabilistic theories could reasonably be found as effective descriptions of physical systems if nature is fundamentally quantum. To this end, we employ a generalized version of noncontextuality: processes that are statistically indistinguishable in an effective theory should not require explanation by multiple distinguishable processes in a more fundamental theory. We formulate this principle in terms of embeddings and simulations of one probabilistic theory by another, show how this concept subsumes standard notions of contextuality, and prove a multitude of fundamental results on approximate embeddings. We show how results on Bell inequalities can be used for the robust certification of generalized contextuality, and use this to propose a novel type of experimental test of quantum theory.