Proposed test of macroscopic quantum contextuality

TL;DR

This paper introduces an inequality for n-qubit systems that noncontextual theories must satisfy, which quantum states violate exponentially with increasing n, demonstrating observable quantum contextuality in complex systems.

Contribution

It presents a new inequality for quantum correlations that reveals exponential violation in multi-qubit systems, advancing understanding of quantum contextuality.

Findings

Quantum inequality violated by all quantum states

Violation grows exponentially with number of qubits

Error tolerance increases with system complexity

Abstract

We show that, for any system with a number of levels which can be identified with n qubits, there is an inequality for the correlations between three compatible dichotomic measurements which must be satisfied by any noncontextual theory, but is violated by any quantum state. Remarkably, the violation grows exponentially with n, and the tolerated error per correlation also increases with n, showing that state-independent quantum contextuality is experimentally observable in complex systems.