Information Causality in the Quantum and Post-Quantum Regime

TL;DR

This paper experimentally investigates the principle of information causality across classical, quantum, and post-quantum regimes, using photonic experiments to simulate super-quantum correlations and analyze fundamental limits of information transfer.

Contribution

It demonstrates a method to simulate stronger-than-quantum correlations via polarization-dependent loss, exploring the role of anisotropic regions in the no-signaling polytope.

Findings

Stronger-than-quantum correlations can be simulated experimentally.

Anisotropic regions are crucial in understanding fundamental principles.

The method applies to studying other fundamental physical principles.

Abstract

Quantum correlations can be stronger than anything achieved by classical systems, yet they are not reaching the limit imposed by relativity. The principle of information causality offers a possible explanation for why the world is quantum and why there appear to be no even stronger correlations. Generalizing the no-signaling condition it suggests that the amount of accessible information must not be larger than the amount of transmitted information. Here we study this principle experimentally in the classical, quantum and post-quantum regimes. We simulate correlations that are stronger than allowed by quantum mechanics by exploiting the effect of polarization-dependent loss in a photonic Bell-test experiment. Our method also applies to other fundamental principles and our results highlight the special importance of anisotropic regions of the no-signalling polytope in the study of fundamental principles.