In a nonlocal scenario, physically isolated players each have a device that inputs and outputs classical information. Certain correlations between the joint input and output of the devices almost uniquely identify the quantum state that they share. This phenomenon is known as self-testing and has applications in quantum cryptography with untrusted devices. It was for example shown that for ever...

The recently reported violation of a Bell inequality using entangled electronic spins in diamonds (Hensen et al., Nature 526, 682-686) provided the first loophole-free evidence against local-realist theories of nature. Here we report on data from a second Bell experiment using the same experimental setup with minor modifications. We find a violation of the CHSH-Bell inequality of 2.35 ± 0.18, i...

By using an alternative, equivalent form of the CHSH inequality and making extensive use of the experimentally testable property of physical locality we determine the 64 different Bell-type inequalities (each one involving four joint probabilities) into which Hardy’s nonlocality theorem can be cast. This allows one to identify all the two-qubit correlations which can exhibit Hardy-type nonlocal...

Elaborating on a previous work by Han et al. [Phys. Lett. A 221 (1996) 283], we provide a general, basis-independent proof of the necessity of negative probability measures in certain local hidden-variable (LHV) models giving a violation of the Bell-CHSH inequality. Moreover, we obtain general solutions for LHV-induced probability measures that reproduce any consistent set of probabilities. PAC...

Karl Svozil† Institut für Theoretische Physik, University of Technology Vienna, Wiedner Hauptstraße 8-10/136, A-1040 Vienna, Austria Abstract Bell-type inequalities and violations thereof reveal the fundamental differences between standard probability theory and its quantum counterpart. In the course of previous investigations ultimate bounds on quantum mechanical violations have been found. Fo...

The Ekert quantum key distribution protocol [1] uses pairs of entangled qubits and performs checks based on a Bell inequality to detect eavesdropping. The 3DEB protocol [5] uses instead pairs of entangled qutrits to achieve better noise resistance than the Ekert protocol. It performs checks based on a Bell inequality for qutrits named CHSH-3 and found in [10, 13]. In this paper, we present a ne...

Quantum nonlocality stands as a resource for device independent quantum information processing (DIQIP), such as, for instance, device independent quantum key distribution. We investigate, experimentally, the assumption of limited measurement dependence, i.e., that the measurement settings used in Bell inequality tests or DIQIP are partially influenced by the source of entangled particle and/or ...

In the experimental verification of Bell’s inequalities in real photonic experiments, it is generally believed that the so-called fair sampling assumption (which means that a small fraction of results provide a fair statistical sample) has an unavoidable role. Here, we want to show that the interpretation of these experiments is really independent of the fair sampling assumption. For this purpo...

In the experimental verification of Bell’s inequalities in real photonic experiments, it is generally believed that the so-called fair sampling assumption (which means that a small fraction of results provide a fair statistical sample) has an unavoidable role. Here, we want to show that the interpretation of these experiments could be feasible, if some different alternative assumptions other th...

Abstract We show that contextual hidden variables including the effect of measuring devices can be backward-propagated by means Green's function to initial Cauchy data. If this data is uncorrelated in spacelike-disjoint sets, CHSH-Bell inequality derived. However, correlation loophole remains unclosed.