Conditions on the compatibility of channels in General Probabilistic Theory and their connection to steering and Bell nonlocality

Martin Plávala

Published 2017-07-27Version 1

We derive general conditions for the compatibility of channels in general probabilistic theory. We introduce new formalism that allows us to easily formulate steering by channels and Bell nonlocality of channels as generalizations of the well-known concepts of steering by measurements and Bell nonlocality of measurements. The generalization does not follow the standard line of thinking stemming from the EPR paradox, but introduces steering and Bell nonlocality as entanglement-assisted incompatibility tests. We show that all of the proposed definitions are, in the special case of measurements, the same as the standard definitions, but not all of the known results for measurements generalize to channels. For example we show that for quantum channels steering is not a necessary condition for Bell nonlocality. We further investigate the new conditions and concepts it the special case of quantum theory and we provide many examples to demonstrate the new concepts and their astonishing implications.