Quantum-Classical Separation in Bounded-Resource Tasks Arising from Measurement Contextuality

TL;DR

This paper demonstrates that quantum contextuality allows certain computational tasks to surpass classical success rates, using a superconducting qubit processor to benchmark quantum advantage through specific games and inequalities.

Contribution

It introduces experimental methods to quantify and utilize quantum contextuality for surpassing classical limits on current quantum hardware.

Findings

Quantum contextuality enables success probabilities beyond classical limits.

Implementation of the magic square game and GHZ game shows quantum advantage.

Proposes new benchmarking techniques based on contextuality.

Abstract

The prevailing view is that quantum phenomena can be harnessed to tackle certain problems beyond the reach of classical approaches. Quantifying this capability as a quantum-classical separation and demonstrating it on current quantum processors has remained elusive. Using a superconducting qubit processor, we show that quantum contextuality enables certain tasks to be performed with success probabilities beyond classical limits. With a few qubits, we illustrate quantum contextuality with the magic square game, as well as quantify it through a Kochen--Specker--Bell inequality violation. To examine many-body contextuality, we implement the N-player GHZ game and separately solve a 2D hidden linear function problem, exceeding classical success rate in both. Our work proposes novel ways to benchmark quantum processors using contextuality-based algorithms.