Determination of molecular energies via variational-based quantum imaginary time evolution in a superconducting qubit system

作     者：Zhiwen Zong Sainan Huai Tianqi Cai Wenyan Jin Ze Zhan Zhenxing Zhang Kunliang Bu Liyang Sui Ying Fei Yicong Zheng Shengyu Zhang Jianlan Wu Yi Yin 

作者机构：Zhejiang Province Key Laboratory of Quantum Technology and DeviceSchool of PhysicsZhejiang UniversityHangzhou 310027China Tencent Quantum LaboratoryShenzhen 518057China 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2024年第67卷第4期

页      面：1-11页

核心收录：

学科分类：07[理学] 070201[理学-理论物理] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.12074336,and 11934010) the National Key Research and Development Program of China(Grant No.2019YFA0308602) the Fundamental Research Funds for the Central Universities in China(Grant No.2020XZZX002-01) the funding support from Tencent Corporation 

主　　题：quantum computation quantum algorithm superconducting qubit 

摘      要：As a valid tool for solving ground state problems,imaginary time evolution(ITE)is widely used in physical and chemical *** ITE-based algorithms in their quantum counterpart have recently been proposed and applied to some real *** experimentally realize the variational-based quantum imaginary time evolution(QITE)algorithm to simulate the ground state energy of hydrogen(H_2)and lithium hydride(Li H)molecules in a superconducting qubit *** H_2 molecule is directly simulated using the 3-qubit circuit with unitary-coupled clusters(UCC)*** also combine QITE with the cluster mean-field(CMF)method to obtain an effective *** Li H molecule is correspondingly simulated using the 3-qubit circuit with hardware-efficient *** comparison,the Li H molecule is also directly simulated using the 4-qubit circuit with UCC ansatz at the equilibrium *** the experimental results show a convergence within 4 iterations,with high-fidelity ground state energy *** a more complex system in the future,the CMF may allow further grouping of interactions to obtain an effective Hamiltonian,then the hybrid QITE algorithm can possibly simulate a relatively large-scale system with fewer qubits.