QUROPE Quantum Information Processing and Communication in Europe

The strength of classical correlations is subject to certain constraints, commonly known as Bell inequalities. Violation of these inequalities is the manifestation of non-locality displayed in particular by quantum mechanics, meaning that quantum mechanics can out-perform classical physics at tasks associated with such Bell inequalities. Interestingly, however, there exist situations in which this is not the case. We associate an intriguing class of bound entangled states, constructed from Unextendible Product Bases (UPBs) with a wide family of tasks, for which (i) quantum correlations do not out-perform the classical ones but (ii) there exist supra-quantum non-signaling correlations that do provide an advantage.