Energy Calculation of Benzene Ring Based on the Variational Quantum Eigensolver Algorithm

In chemical molecular calculations, we usually obtain the most stable structure of molecules by calculating their ground state energy. But the resource and time consumption of these calculations will sharply increase with increasing of the complexity of molecules. Recent years, quantum computing which is a heuristic theory and technology is applied in this field based on the advantage of quantum algorithm. The Variational Quantum Eigensolver (VQE) algorithm which is one of the most promising contemporary applications of quantum computing present excellent powerful for calculating the molecular system energy. In this work, we use three different ansatzs to calculate the energy of the Benzene ring, including our self-designed ansatz and two mainstream ansatzs which are Hardware-Efficient Ansatz and Unitary Coupled Cluster Ansatz. Furthermore, we compare the calculation accuracy and calculation efficiency of the three different types of ansatzs, and investigate the factors influencing ansatz performance by using the calculation result of classical computing technique as the benchmark. Our work contributes to the generalization of the VQE technique to investigate the characteristics of complex molecules, establishing a fresh perspective for commonly employed electronic structure computations.