State-Averaged Orbital-Optimized VQE: A quantum algorithm for the democratic description of ground and excited electronic states

Abstract

The electronic structure problem is one of the main problems in modern theoretical chemistry. While there are many already-established methods both for the problem itself and its applications like semi-classical or quantum dynamics, it remains a computationally demanding task, effectively limiting the size of solved problems. Fortunately, it seems, that offloading some parts of the computation to Quantum Processing Units may offer significant speed-up, often referred to as quantum supremacy or quantum advantage. Together with the potential advantage, this approach simultaneously presents several problems, most notably naturally occurring quantum decoherence, hereafter denoted as quantum noise and lack of large-scale quantum computers, making it necessary to focus on Noisy-Intermediate Scale Quantum computers when developing algorithms aspiring to near-term applications. SA-OO-VQE package aims to answer both these problems with its hybrid quantum-classical conception based on a typical Variational Quantum Eigensolver approach, as only a part of the algorithm utilizes offload to QPUs and the rest is performed on a classical computer, thus partially avoiding both quantum noise and the lack of quantum bits. The SA-OO-VQE has the ability to treat degenerate (or quasi-degenerate) states on the same footing, thus avoiding known numerical optimization problems arising in state-specific approaches around avoided crossings or conical intersections.

References in corpus (7)

• Quantum computational chemistry
• Quantum algorithms for quantum chemistry and quantum materials science
• Elucidating Reaction Mechanisms on Quantum Computers
• Increasing the representation accuracy of quantum simulations of chemistry without extra quantum resources
• A state-averaged orbital-optimized hybrid quantum-classical algorithm for a democratic description of ground and excited states
• Analytical nonadiabatic couplings and gradients within the state-averaged orbital-optimized variational quantum eigensolver
• Analytical energy gradient for state-averaged orbital-optimized variational quantum eigensolvers and its application to a photochemical reaction

Cited by in corpus (3)

• Tangent Space Excitation Ansatz for Quantum Circuits
• Ab Initio Polaritonic Chemistry on Diverse Quantum Computing Platforms: Qubit, Qudit, and Hybrid Qubit-Qumode Architectures
• Transformation-free generation of a quasi-diabatic representation from the state-average orbital-optimized variational quantum eigensolver