Contextuality Test of the Nonclassicality of Variational Quantum Eigensolvers

Understand

Contextuality is an indicator of non-classicality, and a resource for various quantum procedures.

• In this paper, we use contextuality to evaluate the variational quantum eigensolver (VQE), one of the most promising tools for near-term quantum simulation.
• We present an efficiently computable test to determine whether or not the objective function for a VQE procedure is contextual.
• We apply this test to evaluate the contextuality of experimental implementations of VQE, and determine that several, but not all, fail this test of quantumness.