Quantum chemistry calculations on a trapped-ion quantum simulator

TL;DR

This paper demonstrates the use of a trapped-ion quantum simulator to perform quantum chemistry calculations with a hybrid algorithm, showcasing experimental results for molecular energies and discussing noise mitigation strategies.

Contribution

It presents the first experimental implementation of a variational quantum eigensolver on a trapped-ion quantum simulator for molecular ground state calculations.

Findings

Successful calculation of molecular energies for simple molecules

Comparison of different encoding methods on up to four qubits

Analysis of measurement noise and mitigation strategies

Abstract

Quantum-classical hybrid algorithms are emerging as promising candidates for near-term practical applications of quantum information processors in a wide variety of fields ranging from chemistry to physics and materials science. We report on the experimental implementation of such an algorithm to solve a quantum chemistry problem, using a digital quantum simulator based on trapped ions. Specifically, we implement the variational quantum eigensolver algorithm to calculate the molecular ground state energies of two simple molecules and experimentally demonstrate and compare different encoding methods using up to four qubits. Furthermore, we discuss the impact of measurement noise as well as mitigation strategies and indicate the potential for adaptive implementations focused on reaching chemical accuracy, which may serve as a cross-platform benchmark for multi-qubit quantum simulators.