Information-theoretic constraints on correlations with indefinite causal order

Issam Ibnouhsein, Alexei Grinbaum

Published 2014-08-26Version 1

Reconstructions of quantum theory usually implicitly assume that experimental events are ordered within a global causal structure. Using a generalization of the 'process matrix' framework, which accommodates quantum correlations that violate an inequality verified by all causally ordered correlations, we propose three principles constraining bipartite correlations to the quantum bound. We find a promising avenue for an information-theoretic reconstruction of causal structures in quantum theory by choosing a measure of dependence different from mutual information.