Benchmarking quantum computers via protocols

TL;DR

This paper introduces protocol-based benchmarking methods for quantum computers, providing clear thresholds to distinguish quantum from classical behavior and enabling comparisons between different quantum devices and simulators.

Contribution

It proposes seven new benchmarking protocols with quantifiable thresholds, facilitating the assessment of quantum versus classical capabilities in various quantum computing platforms.

Findings

Protocols successfully distinguish quantum from classical behavior.

Comparison of real chips and noisy simulators demonstrates noise characteristics.

Determination of effective qubits and identification of truly-quantum sub-chips.

Abstract

Benchmarking quantum computers often deals with the parameters of single qubits or gates and sometimes deals with algorithms run on an entire chip or a noisy simulator of a chip. Here we propose the idea of using protocols to benchmark quantum computers. The advantage of using protocols, especially the seven suggested here, over other benchmarking methods is that there is a clear cutoff (i.e., a threshold) distinguishing quantumness from classicality for each of our protocols. The protocols we suggest enable a comparison among various circuit-based quantum computers, and also between real chips and their noisy simulators. This latter method may then be used to better understand the various types of noise of the real chips. We use some of these protocols to answer an important question: ``How many effective qubits are there in this N-qubit quantum computer/simulator?'', and we then conclude which effective sub-chips can be named ``truly-quantum''.