1207.3276 (Josh Cadney et al.)

Measurement entropy in Generalized Non-Signalling Theory cannot detect
bipartite non-locality    [PDF]

Josh Cadney, Noah Linden

We consider entropy in Generalized Non-Signalling Theory (also known as box world) where the most common definition of entropy is the measurement entropy. In this setting, we completely characterize the set of allowed entropies for a bipartite state. We find that the only inequalities amongst these entropies are subadditivity and non-negativity. What is surprising is that non-locality does not play a role - in fact any bipartite entropy vector can be achieved by separable states of the theory. This is in stark contrast to the case of the von Neumann entropy in quantum theory, where only entangled states satisfy S(AB)View original: http://arxiv.org/abs/1207.3276