Locally causal and deterministic interpretations of quantum mechanics: parallel lives and cosmic inflation

Abstract

Several locally deterministic interpretations of quantum mechanics are presented and reviewed. The fundamental differences between these interpretations are made transparent by explicitly showing what information is carried locally by each physical system in an idealized experimental test of Bell’s theorem. This also shows how each of these models can be locally causal and deterministic. First, a model is presented which avoids Bell’s arguments through the assumption that space-time inflated from an initial singularity, which encapsulates the entire past light cone of every event in the universe. From this assumption, it is shown how quantum mechanics can produce locally consistent reality by choosing one of many possible futures at the time of the singularity. Secondly, we review and expand the Parallel Lives interpretation of Brassard and Raymond-Robichaud, which maintains local causality and determinism by abandoning the strictest notion of realism. Finally, the two ideas are combined, resulting in a Parallel Lives model in which lives branch apart earlier, under the assumption of a single unified interaction history. The physical content of weak values within each model is discussed, along with related philosophical issues concerning free will.