Reliable Devices Yield Stable Quantum Computations

TL;DR

This paper investigates how temporal and spatial noise variations affect the stability of quantum computations, proposing a bound based on statistical distribution differences to ensure reliable quantum device performance.

Contribution

It introduces a method to quantify noise-induced drift in quantum devices using Hellinger distance and validates an analytical bound linking this distance to computation stability.

Findings

Stability is bounded by Hellinger distance between noise distributions.

Numerical simulations with IBM's transmon model support the bound.

Reliable device characterization improves quantum computation stability.

Abstract

Stable quantum computation requires noisy results to remain bounded even in the presence of noise fluctuations. Yet non-stationary noise processes lead to drift in the varying characteristics of a quantum device that can greatly influence the circuit outcomes. Here we address how temporal and spatial variations in noise relate device reliability to quantum computing stability. First, our approach quantifies the differences in statistical distributions of characterization metrics collected at different times and locations using Hellinger distance. We then validate an analytical bound that relates this distance directly to the stability of a computed expectation value. Our demonstration uses numerical simulations with models informed by the transmon device from IBM called washington. We find that the stability metric is consistently bounded from above by the corresponding Hellinger distance, which can be cast as a specified tolerance level. These results underscore the significance of reliable quantum computing devices and the impact for stable quantum computation.