Information Exchange in Causally Nonseparable Processes

TL;DR

This paper investigates causally nonseparable processes in quantum systems, revealing that the total entropy of two parties quantifies their nonseparability, thus advancing understanding of quantum causal structures.

Contribution

It introduces a novel entropy-based measure for quantifying causally nonseparable processes in quantum systems.

Findings

Total entropy measures nonseparability

Causally nonseparable structures characterized

Advances understanding of quantum causal relations

Abstract

For a system of two parties, the process matrix framework predicts the existence of causally nonseparable structures. We characterize the information exchanged, showing that the total entropy of the two parties acts as a measure for the nonseparability.