Narratability and Cluster Decomposition

Abstract: Recently David Albert presented an argument that relativistic quantum theories are non-narratable. That is, specifying the state on every space-like hypersurface in a given foliation of space-time is not in general sufficient to determine the states on other hypersurfaces, so the history of the universe cannot be told as a narration of states at successive times. We show that the system Albert examined to arrive at this conclusion violates cluster decomposition of the S-matrix, a locality requirement satisfied by relativistic quantum field theories. We formulate the general requirements for a system to display non-narratability, and argue that a large class of systems satisfying them violate the cluster decomposition principle.