Local hidden variable value without optimization procedures.
Dardo Goyeneche, Wojciech Bruzda, Ondřej Turek +2 more
The problem to compute the local hidden variable (LHV) value of a Bell inequality plays a central role in quantum nonlocality. In particular, this problem is the first step to characterize the LHV polytope in a given scenario. In this work, we establish a relation between the LHV value of bipartite Bell inequalities and the mathematical notion of excess of a matrix. Inspired by the strongly developed theory of excess, we derive several results having a direct impact in the field of quantum nonlocality. As consequence, we provide the LHV value for infinite families of bipartite Bell inequalities, with an unbounded number of measurement settings, without requiring to solve any optimization problem. We also find tight Bell inequalities for a large number of measurement settings. Furthermore, we show that the entire set of optimal LHV strategies of Bell inequalities, induced by certain Hadamard matrices, equals the entire set of vectors mutually unbiased to certain pair of bases.
•Nov 23, 2021•0 citations