Quantum Volume in Practice: What Users Can Expect from NISQ Devices

TL;DR

This paper evaluates the practical quantum volume (QV) achievable on current NISQ devices, highlighting the impact of compilation effort and optimization on the reported performance benchmarks.

Contribution

It provides a practical assessment of QV on 24 NISQ devices, emphasizing the importance of compilation and optimization in realistic quantum computing scenarios.

Findings

QV values are lower than official reports due to compilation overhead.

Significant compilation effort is required to achieve optimal QV.

Practical QV depends heavily on classical optimization and compilation.

Abstract

Quantum volume (QV) has become the de-facto standard benchmark to quantify the capability of Noisy Intermediate-Scale Quantum (NISQ) devices. While QV values are often reported by NISQ providers for their systems, we perform our own series of QV calculations on 24 NISQ devices currently offered by IBM Q, IonQ, Rigetti, Oxford Quantum Circuits, and Quantinuum (formerly Honeywell). Our approach characterizes the performances that an advanced user of these NISQ devices can expect to achieve with a reasonable amount of optimization, but without white-box access to the device. In particular, we compile QV circuits to standard gate sets of the vendor using compiler optimization routines where available, and we perform experiments across different qubit subsets. We find that running QV tests requires very significant compilation cycles, QV values achieved in our tests typically lag behind officially reported results and also depend significantly on the classical compilation effort invested.