First-Principles simulations of hydrogen and helium at high pressure

Miguel Morales, University of Illinois, Urbana-Champaign

Hydrogen and helium are the most abundant elements in the universe and their properties are crucial to the understanding of the structure and evolution of giant planets, like Jupiter and Saturn. After a brief introduction to first-principles simulations using Density Functional Theory and Quantum Monte Carlo, I will describe my work on hydrogen-helium mixtures at high pressure. I will present the results of a series of simulations performed at Lawrence Livermore National Laboratory, which allowed us to calculate the free energy and equation of state of the mixture in a large region of phase space. From this work we were able to calculate critical temperatures of immiscibility of helium in dense metallic hydrogen. The results of these calculations have deep implications in the evolutionary theory of Jupiter and Saturn, answering the long-standing question of whether helium phase separates from hydrogen in the interior of the planets.

Abstract Author(s): Miguel Morales