Bell's 1964 theorem, which states that the predictions of quantum theory cannot be
accounted for by any local theory, represents one of the most profound developments in the …

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

Note from the Research Highlights Co-Chairs: A Research Highlights paper appearing in
Communications is usually peer-reviewed prior to publication. The following paper is …

Does quantum theory apply at all scales, including that of observers? New light on this
fundamental question has recently been shed through a resurgence of interest in the long …

Quantum information processing is the emerging field that defines and realizes computing
devices that make use of quantum mechanical principles such as the superposition …

This paper investigates various aspects of the nonlocal effects that can arise when
entangled quantum information is shared between two parties. A natural framework for …

In 1960, the mathematician Ernst Specker described a simple example of nonclassical
correlations, the counter-intuitive features of which he dramatized using a parable about a …

Over 50 years ago, Lovász proved that two graphs are isomorphic if and only if they admit
the same number of homomorphisms from any graph. Other equivalence relations on …

We introduce two families of sum-of-squares (SOS) decompositions for the Bell operators
associated with the tilted Clauser-Horne-Shimony-Holt (CHSH) expressions introduced in …

It is well known that correlations predicted by quantum mechanics cannot be explained by
any classical (local-realistic) theory. The relative strength of quantum and classical …