Ab-initio molecular dynamics for high-pressure liquid Hydrogen

TL;DR

This paper presents a new quantum Monte Carlo-based molecular dynamics scheme for simulating high-pressure liquid hydrogen, enabling large-scale, finite-temperature simulations with reduced force variance and noise-driven dynamics.

Contribution

It introduces an efficient quantum Monte Carlo method for molecular dynamics that accurately computes forces with low variance and incorporates statistical noise for finite-temperature simulations.

Findings

Supports the stability of liquid hydrogen at 300 GPa and 400 K

Enables large-scale simulations with reduced force variance

Demonstrates the feasibility of noise-driven dynamics in quantum Monte Carlo

Abstract

We introduce an efficient scheme for the molecular dynamics of electronic systems by means of quantum Monte Carlo. The evaluation of the (Born-Oppenheimer) forces acting on the ionic positions is achieved by two main ingredients: i) the forces are computed with finite and small variance, which allows the simulation of a a large number of atoms, ii) the statistical noise corresponding to the forces is used to drive the dynamics at finite temperature by means of an appropriate friction matrix. A first application to the high-density phase of Hydrogen is given, supporting the stability of the liquid phase at = 300GP a and = 400K.