Why the Tsirelson Bound?

Abstract

Wheeler’s question ‘why the quantum’ has two aspects: why is the world quantum and not classical, and why is it quantum rather than superquantum, i.e., why the Tsirelson bound for quantum correlations? I discuss a remarkable answer to this question proposed by Pawłowski et al. [1], who provide an information-theoretic derivation of the Tsirelson bound from a principle they call ‘information causality.’