Multi-determinant generalized Hartree-Fock wave functions in Monte Carlo calculations

Chia-Chen Chang; Miguel A. Morales

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arXiv · 1711.02154

Multi-determinant generalized Hartree-Fock wave functions in Monte Carlo calculations

Chia-Chen Chang·Miguel A. Morales

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Abstract

The quantum Monte Carlo algorithm is arguably one of the most powerful computational many-body methods, enabling accurate calculation of many properties in interacting quantum systems. In the presence of the so-called sign problem, the algorithm typically relies on trial wave functions to eliminate the exponential decay of signal-to-noise ratio, usually at the expense of a bias in the result. The quality of the trial state therefore is critical for accurate simulations. In this work, benchmark results of the ground state auxiliary-field quantum Monte Carlo method are reported for the Hubbard model on several geometries. We demonstrate that when multi-determinant generalized Hartree-Fock states are used as trial wave functions, the systematic errors can be systematically reduced to a low level and the results compare favorably with the exact diagonalization data.

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Chia-Chen Chang, Miguel A. Morales. 2017-11-06. Multi-determinant generalized Hartree-Fock wave functions in Monte Carlo calculations. https://arxiv.org/abs/1711.02154

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