Unifying framework for spatial and temporal quantum correlations

Abstract

Measurements on a single quantum system at different times reveal rich non-classical correlations similar to those observed in spatially separated multi-partite systems. Here we introduce a theory framework that unifies the description of temporal, spatial, and spatio-temporal resources for quantum correlations. We identify, and experimentally demonstrate simple cases where an exact mapping between the domains is possible. We then identify correlation resources in arbitrary situations, where not all spatial quantum states correspond to a process and not all temporal measurements have a spatial analogue. These results provide a starting point for the systematic exploration of multi-point temporal correlations as a powerful resource for quantum information processing.