Quantum cryptography is arguably the fastest growing area in quantum information science.
Novel theoretical protocols are designed on a regular basis, security proofs are constantly …

Bell's theorem proves that quantum theory is inconsistent with local physical models. It has
propelled research in the foundations of quantum theory and quantum information science …

Quantum correlations between two parties are essential for the argument of Einstein,
Podolsky, and Rosen in favor of the incompleteness of quantum mechanics. Schrödinger …

Semidefinite programs are convex optimization problems involving a linear objective
function and a domain of positive-semidefinite matrices. Over the past two decades, they …

A central result in the foundations of quantum mechanics is the Kochen-Specker theorem. In
short, it states that quantum mechanics is in conflict with classical models in which the result …

The ability to control multidimensional quantum systems is central to the development of
advanced quantum technologies. We demonstrate a multidimensional integrated quantum …

Self-testing is a method to infer the underlying physics of a quantum experiment in a black
box scenario. As such it represents the strongest form of certification for quantum systems. In …

The security of quantum key distribution (QKD) usually relies on that the users' devices are
well characterized according to the security models made in the security proofs. In contrast …

Although complex numbers are essential in mathematics, they are not needed to describe
physical experiments, as those are expressed in terms of probabilities, hence real numbers …

Quantum theory is commonly formulated in complex Hilbert spaces. However, the question
of whether complex numbers need to be given a fundamental role in the theory has been …