Inspired by Wheeler’s idea of “it from bit”, we helped pioneer an information-theoretic approach to quantum theory. Its central premise is that every quantum system carries only a finite amount of information, with an elementary system corresponding to one bit.

From this viewpoint, key features of quantum theory can be understood as consequences of limited information content. Complementarity expresses the trade-off in knowledge between different observables, entanglement reflects the fact that information in composite systems can reside in correlations, and the constancy of total information is mirrored in the unitary nature of quantum dynamics. These ideas led to an information-theoretic reconstruction of quantum theory, deriving its structure from simple physical principles. (see Recontruction of Quantum Mechanics)