Quantum chemistry beyond Born-Oppenheimer approximation on a quantum computer: a simulated phase estimation study

TL;DR

This paper introduces a quantum algorithm that combines quantum full configuration interaction with the NOMO method to compute molecular energies beyond the Born-Oppenheimer approximation, demonstrated through classical simulations on hydrogen isotopomers.

Contribution

It presents a novel quantum algorithm integrating FCI and NOMO methods for beyond-Born-Oppenheimer calculations, with detailed simulation results.

Findings

Successfully simulated vibrational transition energies for H2 and HT

Demonstrated the algorithm's potential for accurate molecular energy computations

Showed the feasibility of quantum approaches for complex molecular systems

Abstract

We present an efficient quantum algorithm for beyond-Born-Oppenheimer molecular energy computations. Our approach combines the quantum full configuration interaction method with the nuclear orbital plus molecular orbital (NOMO) method. We give the details of the algorithm and demonstrate its performance by classical simulations. Two isotopomers of the hydrogen molecule (H$_2$, HT) were chosen as representative examples and calculations of the lowest rotationless vibrational transition energies were simulated.