Entropy Density Benchmarking of Near-Term Quantum Circuits

TL;DR

This paper introduces an entropy density benchmarking method for quantum circuits, providing a new way to assess quantum device performance and determine the circuit size limit for quantum advantage.

Contribution

It presents a novel entropy accumulation model tested on real quantum hardware, surpassing existing benchmarks in predicting quantum advantage thresholds.

Findings

Entropy density monitoring complements existing benchmarks.

The heuristic model predicts circuit size thresholds for quantum advantage.

Experimental validation on real QPU demonstrates effectiveness.

Abstract

Understanding the limitations imposed by noise on current and next-generation quantum devices is a crucial step towards demonstrating practical quantum advantage. In this work, we investigate the accumulation of entropy density as a benchmark to monitor the performance of quantum processing units. We provide a proof-of-principle demonstration of our novel methodology which entails developing simple heuristic models of how entropy accumulates, testing them against real QPU experiments, and finally using these models to determine a circuit volume threshold above which quantum advantage is unattainable. Monitoring entropy density not only offers a novel approach that complements existing circuit-level benchmarking techniques, but more importantly, it bridges the gap between circuit-level and application-level benchmarking protocols. In particular, our heuristic model of entropy accumulation allows us to outperform existing techniques that bound the circuit size threshold for quantum advantage.