Experimental test of universal complementarity relations

TL;DR

This paper experimentally verifies universal complementarity relations in quantum mechanics, demonstrating that joint measurements of incompatible observables can violate traditional uncertainty bounds, using entangled photonic qubits.

Contribution

The study provides the first experimental verification of universally valid complementarity relations, including an improved relation derived by the authors.

Findings

Violates the Arthurs-Kelly relation in experiments

Uses EPR correlations to measure incompatible observables

Demonstrates the validity of universal complementarity relations

Abstract

Complementarity restricts the accuracy with which incompatible quantum observables can be jointly measured. Despite popular conception, the Heisenberg uncertainty relation does not quantify this principle. We report the experimental verification of universally valid complementarity relations, including an improved relation derived here. We exploit Einstein-Poldolsky-Rosen correlations between two photonic qubits, to jointly measure incompatible observables of one. The product of our measurement inaccuracies is low enough to violate the widely used, but not universally valid, Arthurs-Kelly relation.