Causal Inequalities Challenged by Time-Delocalized Variables.

Researchers have shown that certain processes violating causal inequalities can be realized in the regimes of standard quantum physics, on so-called time-delocalized subsystems. These are physical systems defined by observables that are delocalized over different instants of time, much in the same way as quantum information can be delocalized in space, for instance in quantum error correcting codes. The finding may have far-reaching implications for our understanding of causality in physics.