The HANDE-QMC Project: Open-Source Stochastic Quantum Chemistry from the Ground State Up

Area of Science:

• Computational Quantum Chemistry
• Materials Science
• Electronic Structure Theory

Background:

• Quantum Monte Carlo (QMC) methods, including diffusion Monte Carlo, have advanced electronic structure problem-solving.
• Full Configuration Interaction Quantum Monte Carlo (FCIQMC) provides a systematic pathway to exact solutions for high-accuracy requirements.
• FCIQMC's success spurred the development of Coupled Cluster Monte Carlo (CCMC) and Density Matrix Quantum Monte Carlo (DMQMC).

Purpose of the Study:

• To introduce HANDE-QMC, an open-source software package.
• To implement and provide access to FCIQMC, CCMC, and DMQMC methods.
• To demonstrate the utility of these stochastic quantum chemical methods on diverse systems.

Main Methods:

• Implementation of FCIQMC, CCMC, and DMQMC algorithms within the HANDE-QMC code.
• Inclusion of initiator and semistochastic adaptations for enhanced efficiency.
• Application of the code to model and real solid-state systems and molecular systems.

Main Results:

• Successful demonstration of HANDE-QMC on nitric oxide, the uniform electron gas, and diamond.
• Validation of the implemented stochastic quantum Monte Carlo techniques.
• Provision of an accessible tool for researchers seeking high-accuracy electronic structure calculations.

Conclusions:

• HANDE-QMC serves as a valuable open-source resource for advanced quantum Monte Carlo simulations.
• The code facilitates accurate electronic structure calculations for various chemical and material systems.
• The availability of FCIQMC, CCMC, and DMQMC in a single package promotes wider adoption of these powerful methods.