Mohamed Bourennane

Learn More
We consider two quantum cryptographic schemes relying on encoding the key into qudits, i.e., quantum states in a d-dimensional Hilbert space. The first cryptosystem uses two mutually unbiased bases (thereby extending the BB84 scheme), while the second exploits all d+1 available such bases (extending the six-state protocol for qubits). We derive the(More)
We present a simple and practical protocol for the solution of a secure multiparty communication task, the secret sharing, and its proof-of-principle experimental realization. In this protocol, a secret is split among several parties in a way that its reconstruction requires the collaboration of the participating parties. In our scheme the parties solve the(More)
Quantum correlations are contextual yet, in general, nothing prevents the existence of even more contextual correlations. We identify and test a noncontextuality inequality in which the quantum violation cannot be improved by any hypothetical postquantum theory, and use it to experimentally obtain correlations in which the fraction of noncontextual(More)
We report two fundamental experiments on three-level quantum systems (qutrits). The first one tests the simplest task for which quantum mechanics provides an advantage with respect to classical physics. The quantum advantage is certified by the violation of Wright's inequality, the simplest classical inequality violated by quantum mechanics. In the second(More)
Most proposals for quantum solutions of information-theoretic problems rely on the usage of multi-partite entangled states which are still difficult to produce experimentally with current state-of-the-art technology. Here, we analyze a scheme to simplify a particular kind of multiparty communication protocols for the experiment. We prove that the fidelity(More)
Random access codes (RACs) are used by a party to, with limited communication, access an arbitrary subset of information held by another party. Quantum resources are known to enable RACs that break classical limitations. Here, we study quantum and classical RACs with high-level communication. We derive average performances of classical RACs and present(More)
Photonic systems based on energy-time entanglement have been proposed to test local realism using the Bell inequality. A violation of this inequality normally also certifies security of device-independent quantum key distribution (QKD) so that an attacker cannot eavesdrop or control the system. We show how this security test can be circumvented in(More)
Entanglement is one of the most puzzling features of quantum theory and of great importance for the new field of quantum information. The determination whether a given state is entangled or not is one of the most challenging open problems of the field. Here we report on the experimental demonstration of measurement-device-independent (MDI) entanglement(More)
Quantum mechanics is undoubtedly a weird field of science, which violates many deep conceptual tenets of classical physics, requiring reconsideration of the concepts on which classical physics is based. For instance, it permits persistent correlations between classically separated systems, that are termed as entanglement. To circumvent these problems and(More)
Understanding the characteristics of a quantum systems when affected by noise is one of the biggest challenges for quantum technologies. The general Pauli error channel is an important lossless channel for quantum communication. In this work we consider the effects of a Pauli channel on a pure four-qubit state and simulate the Pauli channel experimentally(More)