Two phase coexistence for the hydrogen-helium mixture

TL;DR

This paper introduces a quantum Monte Carlo algorithm to study hydrogen-helium mixture phase coexistence, achieving results closely matching experimental data and revealing quantum effects at low temperatures and pressures.

Contribution

The authors develop a new quantum Gibbs ensemble Monte Carlo method for simulating hydrogen-helium mixtures, providing highly accurate phase coexistence results.

Findings

Results agree within 15% of experimental data

Quantum effects are significant at low temperatures and pressures

Helium in vapor phase shows superfluidity at extremely low temperatures

Abstract

We use our newly constructed quantum Gibbs ensemble Monte Carlo algorithm to perform computer experiments for the two phase coexistence of a hydrogen-helium mixture. Our results are in quantitative agreement with the experimental results of C. M. Sneed, W. B. Streett, R. E. Sonntag, and G. J. Van Wylen. The difference between our results and the experimental ones is in all cases less than 15% relative to the experiment, reducing to less than 5% in the low helium concentration phase. At the gravitational inversion between the vapor and the liquid phase, at low temperatures and high pressures, the quantum effects become relevant. At extremely low temperature and pressure the first component to show superfluidity is the helium in the vapor phase.