# QMCPACK: Advances in the development, efficiency, and application of auxiliary field and real-space variational and diffusion quantum Monte Carlo.

@article{Kent2020QMCPACKAI, title={QMCPACK: Advances in the development, efficiency, and application of auxiliary field and real-space variational and diffusion quantum Monte Carlo.}, author={Paul R. C. Kent and Abdulgani Annaberdiyev and Anouar Benali and M Chandler Bennett and Edgar Josu{\'e} Landinez Borda and Peter W. Doak and Hongxia Hao and Kenneth D. Jordan and Jaron T. Krogel and Ilkka Kyl{\"a}np{\"a}{\"a} and Joonho Lee and Ye Luo and Fionn D. Malone and Cody A Melton and Lubos Mitas and Miguel A. Morales and Eric Neuscamman and Fernando A Reboredo and Brenda M. Rubenstein and Kayahan Saritas and Shiv Upadhyay and Guangming Wang and Shuai Zhang and Luning Zhao}, journal={The Journal of chemical physics}, year={2020}, volume={152 17}, pages={ 174105 } }

We review recent advances in the capabilities of the open source ab initio Quantum Monte Carlo (QMC) package QMCPACK and the workflow tool Nexus used for greater efficiency and reproducibility. The auxiliary field QMC (AFQMC) implementation has been greatly expanded to include k-point symmetries, tensor-hypercontraction, and accelerated graphical processing unit (GPU) support. These scaling and memory reductions greatly increase the number of orbitals that can practically be included in AFQMC…

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## 47 Citations

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## References

SHOWING 1-10 OF 179 REFERENCES

Ab initio computations of molecular systems by the auxiliary‐field quantum Monte Carlo method

- Chemistry
- 2017

The auxiliary‐field quantum Monte Carlo (AFQMC) method provides a computational framework for solving the time‐independent Schrödinger equation in atoms, molecules, solids, and a variety of model…

QMCPACK: an open source ab initio quantum Monte Carlo package for the electronic structure of atoms, molecules and solids.

- PhysicsJournal of physics. Condensed matter : an Institute of Physics journal
- 2018

The QMCPACK code is specifically optimized for calculations with large numbers of electrons on the latest high performance computing architectures, including multicore central processing unit and graphical processing unit systems.

Accurate atomic correlation and total energies for correlation consistent effective core potentials.

- PhysicsJournal of chemical theory and computation
- 2020

The results offer a clear benchmark for future high accuracy calculations in a broad variety of correlated wave function methods such as CI and CC as well is in stochastic approaches such as real space sampling QMC.

Frozen-Orbital and Downfolding Calculations with Auxiliary-Field Quantum Monte Carlo.

- PhysicsJournal of chemical theory and computation
- 2013

A generalization of the frozen-orbital approach that downfolds high-energy basis states to a physically relevant low-energy sector, which allows a systematic approach to produce realistic model Hamiltonians to further increase efficiency for extended systems.

Multideterminant Wave Functions in Quantum Monte Carlo.

- ChemistryJournal of chemical theory and computation
- 2012

This Perspective presents a systematic application of large scale multideterminant expansions in QMC and demonstrates the potential of this strategy for systematically reducing the fixed-node error in the wave function and for achieving chemical accuracy in energy predictions.

Auxiliary-field quantum Monte Carlo calculations with multiple-projector pseudopotentials

- Physics
- 2017

We have implemented recently developed multiple-projector pseudopotentials into the planewave based auxiliary-field quantum Monte Carlo (pw-AFQMC) method. Multiple-projector pseudopotentials can…

Computing the energy of a water molecule using multideterminants: a simple, efficient algorithm.

- PhysicsThe Journal of chemical physics
- 2011

A method for working with multi-Slater-Jastrow wave functions in QMC codes that is easy to implement, efficient both in computational speed as well as memory, and easily parallelized is described.

Investigation of a Quantum Monte Carlo Protocol To Achieve High Accuracy and High-Throughput Materials Formation Energies.

- Materials Science, PhysicsJournal of chemical theory and computation
- 2017

This work evaluates the use of quantum Monte Carlo (QMC) to calculate material formation energies in a high-throughput environment, and determines a set of accurate pseudopotentials in QMC via a systematic investigation of multiple available pseudopotential libraries.

A new scheme for fixed node diffusion quantum Monte Carlo with pseudopotentials: Improving reproducibility and reducing the trial-wave-function bias.

- Computer ScienceThe Journal of chemical physics
- 2019

DLA paves the way to the automation of FN-DMC and its much easier application in large systems by providing good quality results and stable simulations that are slightly more efficient than LA and TM.

Density functional orbitals in quantum Monte Carlo: The importance of accurate densities.

- PhysicsThe Journal of chemical physics
- 2019

It is found that the accuracy of the density is a strong indicator of the quality of the many-body nodal surface produced by a determinant of the corresponding Kohn-Sham orbitals, and suggests that prioritizing accurate densities in the future development of DFAs would also contribute to the continued improvement of DMC.