Shortcut to Chemically Accurate Quantum Computing via Density-based Basis-set Correction

TL;DR

This paper introduces a density-based basis-set correction method that accelerates quantum chemistry calculations on quantum computers, reducing resource requirements while maintaining chemical accuracy for molecules.

Contribution

It presents a novel approach coupling basis-set correction with quantum ansatz to achieve accurate results with fewer qubits, enabling practical quantum chemistry computations.

Findings

Accelerates basis-set convergence for quantum chemistry calculations.

Improves electronic densities, energies, and properties with fewer qubits.

Can serve as a classical correction for quantum hardware results.

Abstract

Using GPU-accelerated state-vector emulation, we propose to embed a quantum computing ansatz into density-functional theory via density-based basis-set corrections (DBBSC) to obtain quantitative quantum-chemistry results on molecules that would otherwise require brute-force quantum calculations using hundreds of logical qubits. Indeed, accessing a quantitative description of chemical systems while minimizing quantum resources is an essential challenge given the limited qubit capabilities of current quantum processors. We provide a shortcut towards chemically accurate quantum computations by approaching the complete-basis-set limit through coupling the DBBSC approach, applied to any given variational ansatz, to an on-the-fly crafting of basis sets specifically adapted to a given system and user-defined qubit budget. The resulting approach self-consistently accelerates the basis-set convergence, improving electronic densities, ground-state energies, and first-order properties (e.g. dipole moments), but can also serve as a classical, a posteriori, energy correction to quantum hardware calculations with expected applications in drug design and materials science.