Auxiliary-Field Quantum Monte Carlo

The AFQMC library aims to provide a comprehensive software environment using auxiliary-field quantum Monte Carlo, broadly defined, to study quantum many-fermion systems.

The library will contain a suite of software for
1. correlated electron models and ultracold fermionic atom systems
2. molecular calculations treating standard quantum chemistry Hamiltonians (for example, using Gaussian basis sets)
3. ab initio calculations in extended systems with planewaves and pseudopotentials

These software programs implement importance-sampled branching random walks in non-orthogonal Slater determinant space. A constrained-path or phaseless approximation is used to control the fermion sign or phase problem. Total energy, as well as other observables and correlation functions, is computed.

The packages above use a ground-state, canonical ensemble formalism. Corresponding finite-temperature software is also being developed.

The software is being developed by a core group of developers at CCQ, College of William & Mary and elsewhere, collaborating closely. As it becomes more mature, the software will be made publicly available and transitioned into community codes.

A pedagogical AFQMC package for model systems, written in Matlab and with a graphical interface, is available at here.

Project Leader: Miguel Morales, Shiwei Zhang

Project Scientists: Thomas Hahn

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