Numerical Simulations of Noisy Quantum Circuits for Computational Chemistry

TL;DR

This paper uses numerical simulations to analyze how noise affects the accuracy of quantum circuits in estimating molecular ground states, focusing on the impact of noise, circuit depth, and optimization methods.

Contribution

It introduces a detailed simulation framework to evaluate the effects of noise on variational quantum eigensolver circuits for molecular energy estimation.

Findings

Energy error increases with noise levels and circuit depth.

Fidelity decreases as gate noise and complexity grow.

Optimization methods influence the accuracy of ground-state estimates.

Abstract

The opportunities afforded by near-term quantum computers to calculate the ground-state properties of small molecules depend on the structure of the computational ansatz as well as the errors induced by device noise. Here we investigate the behavior of these noisy quantum circuits using numerical simulations to estimate the accuracy and fidelity of the prepared quantum states relative to the ground truth obtained by conventional means. We implement several different types of ansatz circuits derived from unitary coupled cluster theory for the purposes of estimating the ground-state energy of Sodium Hydride using the variational quantum eigensolver algorithm. We show how relative error in the energy and the fidelity scale with the levels of gate-based noise, the inter-molecular configuration, the ansatz circuit depth, and the parameter optimization methods.