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

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.