Validation of the Ability of Full Configuration Interaction Quantum Monte Carlo for Studying the 2D Hubbard Model
Su-Jun Yun1,3**, Tie-Kuang Dong2, Shi-Ning Zhu3
1School of Electronic Engineering, Nanjing Xiaozhuang University, Nanjing 211171 2Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 3School of Physics, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093
Abstract：To validate the ability of full configuration interaction quantum Monte Carlo (FCIQMC) for studying the 2D Hubbard model near half-filling regime, the ground state energies of a $4\times4$ square lattice system with various interaction strengths are calculated. It is found that the calculated results are in good agreement with those obtained by exact diagonalization (i.e., the exact values for a given basis set) when the population of psi particles (psips) is higher than the critical population required to correctly sample the ground state wave function. In addition, the variations of the average computational time per 20 Monte Carlo cycles with the coupling strength and the number of processors are also analyzed. The calculated results show that the computational efficiency of an FCIQMC calculation is mainly affected by the total population of psips and the communication between processors. These results can provide useful references for understanding the FCIQMC algorithm, studying the ground state properties of the 2D Hubbard model for the larger system size by the FCIQMC method and using a computational budget as effectively as possible.
. [J]. 中国物理快报, 2017, 34(8): 80201-.
Su-Jun Yun, Tie-Kuang Dong, Shi-Ning Zhu. Validation of the Ability of Full Configuration Interaction Quantum Monte Carlo for Studying the 2D Hubbard Model. Chin. Phys. Lett., 2017, 34(8): 80201-.
2017, Vol. 34 
