Popescu-Rohrlich box fraction of nonobjective information and distinguishing quantum theory

TL;DR

This paper explores the limitations of information-theoretic criteria in distinguishing quantum theory from more general nonsignaling theories, introducing the Popescu-Rohrlich box fraction as a new tool for this purpose.

Contribution

It introduces the concept of Popescu-Rohrlich box fraction of nonobjective information to better differentiate quantum theory from generalized nonsignaling models.

Findings

Popescu-Rohrlich box fraction can identify nonobjective information in nonsignaling models.

Information causality alone does not fully distinguish quantum from postquantum theories.

Postquantum models are isolated by the Popescu-Rohrlich box fraction in Bell-local boxes.

Abstract

It is demonstrated that identifying information-theoretic limitations of quantum Bell nonlocality alone cannot completely distinguish quantum theory from generalized nonsignaling theories. To this end, an information-theoretic concept of certifying nonobjective information by the Popescu-Rohrlich box fraction is employed. Furthermore, in the aforementioned demonstration, a partial answer to the question of what distinguishes quantum theory from generalized nonsignaling theories emerges beyond the one provided by the principle of information causality alone. This is accomplished by demonstrating that postquantum models identified by the information causality are isolated by the emergence of the Popescu-Rohrlich box fraction of nonobjective information in Bell-local boxes of a nonsignaling model, over the other nonsignaling models.