Coupled Electron Ion Monte Carlo Calculations of Atomic Hydrogen

TL;DR

This paper introduces a novel Monte Carlo approach combining Path Integral and Quantum Monte Carlo methods to study metallic hydrogen at high pressures, revealing more detailed structure and higher melting points than previous simulations.

Contribution

The paper develops a new coupled Monte Carlo method bridging finite temperature proton dynamics with ground state electron calculations, advancing simulations of dense hydrogen.

Findings

More detailed structural data of metallic hydrogen

Higher melting temperatures than previous LDA-based results

Insights into quantum proton motion and zero-temperature behavior

Abstract

We present a new Monte Carlo method which couples Path Integral for finite temperature protons with Quantum Monte Carlo for ground state electrons, and we apply it to metallic hydrogen for pressures beyond molecular dissociation. This method fills the gap between high temperature electron-proton Path Integral and ground state Diffusion Monte Carlo methods. Our data exhibit more structure and higher melting temperatures of the proton crystal than Car-Parrinello Molecular Dynamics results using LDA. We further discuss the quantum motion of the protons and the zero temperature limit.