Experimental Determination of Multi-Qubit Ground State via a Cluster Mean-Field Algorithm
Ze Zhan, Chongxin Run, Zhiwen Zong, Xiang, Liang, Ying Fei, Wenyan Jin, Zhi-Long Jia, Peng Duan, Jianlan Wu, Yi Yin, Guo‐Ping Guo · arXiv (Cornell University) · 2021
A quantum eigensolver is designed under a multi-layer cluster mean-field (CMF) algorithm by partitioning a quantum system into spatially-separated clusters. For each cluster, a reduced Hamiltonian is obtained after a partial average over its environment cluster. The products of eigenstates from different clusters construct a compressed Hilbert space, in which an effective Hamiltonian is diagonalized to determine certain eigenstates of the whole Hamiltonian. The CMF method is numerically verified in multi-spin chains and experimentally studied in a fully-connected three-spin network, both yielding an excellent prediction of their ground states.