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Chemistry

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Selected Works

2014

Hubbard Model

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Full-Text Articles in Physical Sciences and Mathematics

An Adaptive, Kink-Based Approach To Path Integral Calculations, Randal W. Hall Oct 2014

An Adaptive, Kink-Based Approach To Path Integral Calculations, Randal W. Hall

Randall W. Hall

A kink-based expression for the canonical partition function is developed using Feynman’s path integral formulation of quantum mechanics and a discrete basis set. The approach is exact for a complete set of states. The method is tested on the 3×3 Hubbard model and overcomes the sign problem seen in traditional path integral studies of fermion systems. Kinks correspond to transitions between different N-electron states, much in the same manner as occurs in configuration interaction calculations in standard ab initio methods. The different N-electron states are updated, based on which states occur frequently during a Monte Carlo simulation, giving better estimates …


An Adaptive, Kink-Based Approach To Path Integral Calculations, Randal W. Hall Oct 2014

An Adaptive, Kink-Based Approach To Path Integral Calculations, Randal W. Hall

Randall W. Hall

A kink-based expression for the canonical partition function is developed using Feynman’s path integral formulation of quantum mechanics and a discrete basis set. The approach is exact for a complete set of states. The method is tested on the 3×3 Hubbard model and overcomes the sign problem seen in traditional path integral studies of fermion systems. Kinks correspond to transitions between different N-electron states, much in the same manner as occurs in configuration interaction calculations in standard ab initio methods. The different N-electron states are updated, based on which states occur frequently during a Monte Carlo simulation, giving better estimates …