Quantum Computation of Hydride Ion using Variational Quantum Algorithm

Abstract Because of remarkable reactivity and strong electron‐electron correlation effects, the precise prediction of ground state energy and chemical reactivity of hydride ion is an essential objective in quantum chemistry. Leveraging variational quantum algorithms offers a promising avenue for studying molecular properties using current noisy intermediate‐scale quantum devices. This work utilises the variational approach to anticipate the ground state, reactivity, and single‐electron detachment energy of the three‐body hydride ion. We investigated both Hardware‐Efficient Ansatz (HEA) and Chemistry‐inspired ansatz based on a Unitary Coupled Cluster (UCC) on both noiseless and noisy IBM simulators. Modern error‐mitigating techniques, such as Zero‐Noise Extrapolation (ZNE) with unitary folding and measurement error mitigation, have been implemented to significantly reduce errors in noisy environments. This study contributes to our understanding of the quantum computational nuances of the hydride ion and addresses the question of whether quantum computers can retain the correlation energies for these correlated ions.