Proof-of-principle experimental demonstration of quantum gate verification

TL;DR

This paper demonstrates a proof-of-principle optical experiment for quantum gate verification, showing it requires significantly fewer samples than traditional methods to confirm high fidelity of quantum gates.

Contribution

It provides the first experimental validation of the quantum gate verification scheme, highlighting its efficiency over standard quantum process tomography.

Findings

QGV requires ~300 samples for 97% fidelity confirmation at 99% confidence.

Standard quantum process tomography needs ~3000 samples for the same result.

QGV has potential for widespread use in quantum device evaluation.

Abstract

To employ a quantum device, the performance of the quantum gates in the device needs to be evaluated first. Since the dimensionality of a quantum gate grows exponentially with the number of qubits, evaluating the performance of a quantum gate is a challenging task. Recently, a scheme called quantum gate verification (QGV) has been proposed, which can verifies quantum gates with near-optimal efficiency. In this paper, we implement a proof-of-principle optical experiment to demonstrate this QGV scheme. We show that for a single-qubit quantum gate, only $\sim300$ samples are needed to confirm the fidelity of the quantum gate to be at least $97\%$ with a $99\%$ confidence level using the QGV method, whereas, at least $\sim3000$ samples are needed to achieve the same result using the standard quantum process tomography method. The QGV method validated by this paper has the potential to be widely used for the evaluation of quantum devices in various quantum information applications.