Natasha Oughton (Oxford): The significance of the Information Causality principle in singling out quantum correlations
The Information Causality (IC) principle has been proposed, in conjunction with no-signalling, to re-axiomatize quantum mechanics. From this principle we can re-derive the quantum limit on correlations by constraining the amount of information that can be gained after sending a number of classical bits. However, I show that despite appearing intuitive, this derivation rests on the choice of the Shannon information as the appropriate measure of information sent. I argue that this choice is merely conventional, and further that an alternative uncertainty measure no longer arrives at the quantum bound, concluding that the IC principle lacks sufficient justification to play a foundational role.