K-ADAPT-VQE: Optimizing Molecular Ground State Searches by Chunking Operators

TL;DR

K-ADAPT-VQE introduces a chunking strategy to improve the efficiency of variational quantum eigensolvers in molecular ground state calculations, significantly reducing computational resources needed.

Contribution

It proposes a novel chunking approach for operator addition in ADAPT-VQE, enhancing efficiency over traditional methods.

Findings

Reduces total VQE iterations

Decreases quantum function calls

Achieves chemical accuracy more efficiently

Abstract

Classical simulation of molecular systems is limited by exponential scaling, a hurdle quantum algorithms like Variational Quantum Eigensolvers (VQEs) aim to overcome. Although ADAPT-VQE enhances VQEs by dynamically building ans\"atze, it can remain computationally intensive. This work presents K-ADAPT-VQE, which improves efficiency by adding operators in chunks of K at each iteration. Our results from simulating small molecular systems show that K-ADAPT-VQE substantially reduces the total number of VQE iterations and quantum function calls required to achieve chemical accuracy in molecular ground state calculations.