Quantum simulation of low temperature metallic hydrogen

A snapshot from the ab-initio path-integral molecular dynamics simulation where a metallic liquid phase is found at 900 GPa and 50 K. Accounting for the quantum nature of the nuclei is essential for the appearance of this low-temperature metallic phase.

A snapshot from the ab-initio path-integral molecular dynamics simulation where a metallic liquid phase is found at 900 GPa and 50 K. Accounting for the quantum nature of the nuclei is essential for the appearance of this low-temperature metallic phase.

The nature of dense hydrogen is a central problem in physics and its abundance, for example, in gas giants such as Jupiter and Saturn means that it is critical to our understanding of the universe. In spite of the tremendous progress made over the last 80 years, important gaps in our understanding of the hydrogen phase diagram remain, with arguably the most challenging issue being the solid to liquid melting transition at ultra-high pressures.

This study, involving a group of researchers from the Thomas Young Centre at UCL, as well as from Peking University, Cambridge and York, presents a fundamental advance in the understanding of dense hydrogen which has far reaching implications for a wide range of scientific fields.

The scientists from the four universities looked, in an international effort, at the melting of hydrogen by computer simulation of the coexistence of the solid and liquid phases, for the first time taking the quantum motion of the protons into account explicitly. The findings show a low-temperature metallic atomic liquid phase of hydrogen at pressures 900 GPa and above, down to 50K, the lowest temperature that can be reliably simulated. The existence of this low temperature liquid is associated with a negative slope of the melting line between atomic liquid and solid phases at pressures between 500 and 800 GPa. These results are highly quantum in nature, with classical simulations demonstrating completely different behaviour, with the simulations showing considerably higher melting points. This study confirms the existence of this phase in simulations and shows how the quantum motion of the protons plays a critical role in its stabilisation.

This work has been published in Nature Communications

Journal link:Nature Communications

News

IMG-20190720-WA0002

Science and sports in York

Last weekend, the ICE group gathered in York for the International Materials Simulation Workshop. Current and former members as well as collaborators talked about their recent projects and discussed how to tackle society’s big challenges, utilize advancements in methodology and make the most of fruitful collaborations. The meeting highlighted the diverse range of problems that […]

0 comments
ice_triathlon

Triple Triathlon at Castle Howard in support of WaterAid

The ICE group will be participating in the Castle Triathlon series for the third year in a row. This time, three relays teams are going to compete at Castle Howard, near York, on 21 July. They will be swimming, cycling and running a combined distance of roughly 280 km! As part of the tradition, the […]

0 comments
ice_logo_5_rect

Open postdoc position (University of Manchester & ICE group)

A 2-year postdoc position is available in the Condensed Matter Physics group at the University of Manchester. The project will be carried out in collaboration with the ICE group and involves developing and applying theoretical models to understand the anomalous dielectric behaviour of water under confinement (Fumagalli et al. Science 360, 1339-1342, 2018). You can […]

0 comments
Angelos_London-Marathon

Angelos sets world record at the London Marathon!

Angelos set a new world record for the “fastest marathon dressed as a scientist (male)” at this year’s London Marathon, finishing in 3:22:51. Congratulations! He also managed to raise more than £3000 in support of WaterAid, an international charity working to provide clean water and decent toilets to people all over the world. Many thanks […]

0 comments
ice_logo_5_rect

Welcome Julia!

The ICE group has a new member: Julia will be working on C-H activation at single-atom alloy catalysts. The project involves collaboration with Michail Stamatakis from UCL’s Department of Chemical Engineering. We hope you will have a pleasant and productive time in the ICE group!

0 comments
ice-surface_NatureReviewsChemistry

Nature Reviews Chemistry on surface premelting of water ice published!

In a recently published Nature Reviews Chemistry article, titled “Surface premelting of water ice”, Ben Slater and Angelos review the current understanding of the quasi-liquid layer (QLL) that forms on the surface of ice. The review describes how advances in experimental and computational techniques furthered our understanding in the years since Faraday first postulated the […]

0 comments
angelos_world-record

Angelos is trying to set a new world record!

Angelos will be running this year’s London Marathon with the aim of setting a new world record for the “fastest marathon dressed as a scientist (male)”. He is running in support of WaterAid, an international charity working to provide clean water and decent toilets to people all over the world. To find out more and […]

0 comments
trophy

Patrick wins Best Poster prize at the TYC Student Day!

For his contribution “A Machine Learning Potential for Carbon”, Patrick was awarded a Best Poster prize at this year’s TYC Student Day! He was one of the four winners chosen from more than 30 poster presentations, which highlighted the excellent research conducted within the Thomas Young Centre. Patrick had also won the Best Poster prize […]

0 comments
incite_titan_summit

INCITE grant awarded for quantum Monte Carlo project!

The proposal titled “New Frontiers for Material Modeling via Machine Learning Techniques with Quantum Monte Carlo” was awarded a 2019 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) grant by the U.S. Department of Energy’s Office of Science. The project lead by Dario Alfè and in collaboration with Gábor Csányi in Cambridge involves […]

0 comments
Group_1

Welcome new ICE group members!

We are happy to welcome some new people who joined the group over the last few weeks. Tai is doing a postdoc in a joint UCL – BP project. Fabian is sharing his PhD time between UCL and Imperial College. Michael already did his Master project in our group and is now continuing his work […]

0 comments

Group gatherings