High pressure hydrogen by machine learning and quantum Monte Carlo

Abstract

We have developed a technique combining the accuracy of quantum Monte Carlo in describing the electron correlation with the efficiency of a Machine Learning Potential (MLP). We use kernel regression in combination with SOAP (Smooth Overlap of Atomic Position) features, implemented here in a very efficient way. The key ingredients are: i) a sparsification technique, based on farthest point sampling, ensuring generality and transferability of our MLPs and ii) the so called $\Delta$-learning, allowing a small training data set, a fundamental property for highly accurate but computationally demanding calculations, such as the ones based on quantum Monte Carlo. As the first application we present a benchmark study of the liquid-liquid transition of high-pressure hydrogen and show the quality of our MLP, by emphasizing the importance of high accuracy for this very debated subject, where experiments are difficult in the lab, and theory is still far from being conclusive.

revised exposition, performed more validation tests. Comments welcome!

References in corpus (6)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Canonical sampling through velocity-rescaling
• Hydrogen-Helium Mixtures in the Interiors of Giant Planets
• Phase diagram of hydrogen and a hydrogen-helium mixture at planetary conditions by Quantum Monte Carlo simulations
• Quantum Monte Carlo Simulation of the High-Pressure Molecular-Atomic Crossover in Fluid Hydrogen
• Space-warp coordinate transformation for efficient ionic force calculations in quantum Monte Carlo

Cited by in corpus (5)

• Stable solid molecular hydrogen above 900K from a machine-learned potential trained with diffusion Quantum Monte Carlo
• Deep Variational Free Energy Approach to Dense Hydrogen
• Principal deuterium Hugoniot via Quantum Monte Carlo and $\Delta$-learning
• A structural optimization algorithm with stochastic forces and stresses
• Extending the reach of quantum computing for materials science with machine learning potentials