Scalable noncontextuality inequalities and certification of multiqubit quantum systems

TL;DR

This paper introduces scalable noncontextuality inequalities for certifying multiqubit quantum systems without requiring spatial separation, leveraging measurement compatibility, and demonstrating robustness against errors.

Contribution

It presents a novel family of noncontextuality inequalities that are scalable and applicable for certifying multiqubit systems without spatial separation.

Findings

Inequalities are scalable with polynomial complexity.

The scheme is robust to experimental errors.

Applicable in scenarios lacking spatial separation.

Abstract

We propose a family of noncontextuality inequalities and show that they can be used for certification of multiqubit quantum systems. Our scheme, unlike those based on non-locality, does not require spatial separation between the subsystems, yet it makes use of certain compatibility relations between measurements. Moreover, it is scalable in the sense that the number of expectation values that are to be measured to observe contextuality scales polynomially with the number of qubits that are being certified. In a particular case we also show our scheme to be robust errors and experimental imperfections. Our results seem promising as far as certification of physical set-ups is concerned in scenarios where spatial separation between the subsystems cannot be guaranteed.