The goal of the paper is to check whether the real eigenstates of the observables in the single qudit Pauli group may lead to quantum contextuality, the property that mutually compatible and independent experiments depend on each other. We find that quantum contextuality crops up at dimension twelve in various configurations with a few rays. We use the Shannon capacity for characterizing the co...

Locality and non-contextuality are intuitively appealing features of classical physics, which are contradicted by quantum mechanics. The goal of the classic no-go theorems by Bell, Kochen-Specker, et al. is to show that non-locality and contextuality are necessary features of any theory whose predictions agree with those of quantum mechanics. We use the mathematics of sheaf theory to analyze th...

We report the first state-independent experimental test of quantum contextuality on a single photonic qutrit (three-dimensional system), based on a recent theoretical proposal [Phys. Rev. Lett. 108, 030402 (2012)]. Our experiment spotlights quantum contextuality in its most basic form, in a way that is independent of either the state or the tensor product structure of the system.

Contextuality is a fundamental property of quantum theory and a critical resource for quantum computation. Here, we experimentally observe the arguably cleanest form of contextuality in quantum theory [A. Cabello et al., Phys. Rev. Lett. 111, 180404 (2013)] by implementing a novel method for performing two sequential measurements on heralded photons. This method opens the door to a variety of f...

The main topic of this thesis is the study of contextuality, a key characteristic feature of quantum mechanics that represents one of the most valuable resources for quantum computation. We will adopt the sheaf-theoretic approach to non-locality and contextuality introduced in [AB11]. This elegant mathematical theory will enable us to consider contextuality on a higher scale, as a general, abst...

We propose a principled way of defining and measuring contextuality in systems with deterministic inputs and random outputs. We illustrate it on systems with two binary inputs and two binary random outputs, the prominent example being the system of two entangled spin-half particles with each particle’s spins (random outputs) being measured along one of two directions (inputs). It is traditional...

1. Introduction Contextuality is trivially pervasive: all human experience takes place in endlessly changing environments and inexorably moving time frames. In order to have any meaning, the changing items must be placed within a more stable setting, a framework that is not subject to the same kind of contextual change. Total contextuality collapses into chaos, or becomes ineffable. While basic...

Recent work by Abramsky and Brandenburger used sheaf theory to give a mathematical formulation of non-locality and contextuality. By adopting this viewpoint, it has been possible to define cohomological obstructions to the existence of global sections. In the present work, we illustrate new insights into different aspects of this theory. We shed light on the power of detection of the cohomologi...

Contextuality in quantum physics provides a key resource for quantum information and computation. The topological approach in [3, 2] characterizes contextuality as “global inconsistency” coupled with “local consistency”, revealing it to be a phenomenon also found in many other fields. This has yielded a logical method of detecting and proving the “global inconsistency” part of contextuality. Ou...

In this paper we discuss the use of quantum mechanics to model psychological experiments, starting by sharply contrasting the need of these models to use quantum mechanical nonlocality instead of contextuality. We argue that contextuality, in the form of quantum interference, is the only relevant quantum feature used. Nonlocality does not play a role in those models. Since contextuality is also...