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Main Authors: Karasiev, Valentin V., Hu, S. X., Hinz, Joshua P., Goshadze, R. M. N., Zhang, Shuai, Bergermann, Armin, Redmer, Ronald
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.23152
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author Karasiev, Valentin V.
Hu, S. X.
Hinz, Joshua P.
Goshadze, R. M. N.
Zhang, Shuai
Bergermann, Armin
Redmer, Ronald
author_facet Karasiev, Valentin V.
Hu, S. X.
Hinz, Joshua P.
Goshadze, R. M. N.
Zhang, Shuai
Bergermann, Armin
Redmer, Ronald
contents Accurate knowledge of the electrical and thermal conductivities and structural properties of hydrogen-helium mixtures under thermodynamic conditions within and beyond the immiscibility range is very important to predict the thermal evolution and internal structure of gas giant planets like Jupiter and Saturn. Here, we propose a novel method to determine the immiscibility boundary accurately without the need for free energy calculations, while providing consistent insights into structural and transport properties of mixtures. We show with direct large-scale ab initio simulations that the insulator-metal transition (IMT) of the hydrogen subsystem is strongly affected by an admixture with a small fraction of helium and occurs at temperatures significantly higher than those of pure hydrogen. At pressures below 150 GPa, the IMT boundary is not related anymore to the H2 subsystem dissociation, the system remains insulating even after the full dissociation of H2 molecules and its transition to an H-He mixture. The offset of the IMT in the H-He mixture relative to the dissociation region in the hydrogen subsystem and the significant reduction of static electrical and thermal conductivity by a factor between two and a few thousand relative to pure hydrogen found in mixtures have consequences for Jupiter and Saturn's thermal evolution, internal structure, and dynamo action, affecting a large fraction of the interior of both planets.
format Preprint
id arxiv_https___arxiv_org_abs_2601_23152
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Direct simulations of H-He mixtures at planetary interior conditions: demixing, insulator-metal transition and miscibility boundaries
Karasiev, Valentin V.
Hu, S. X.
Hinz, Joshua P.
Goshadze, R. M. N.
Zhang, Shuai
Bergermann, Armin
Redmer, Ronald
Earth and Planetary Astrophysics
Materials Science
Accurate knowledge of the electrical and thermal conductivities and structural properties of hydrogen-helium mixtures under thermodynamic conditions within and beyond the immiscibility range is very important to predict the thermal evolution and internal structure of gas giant planets like Jupiter and Saturn. Here, we propose a novel method to determine the immiscibility boundary accurately without the need for free energy calculations, while providing consistent insights into structural and transport properties of mixtures. We show with direct large-scale ab initio simulations that the insulator-metal transition (IMT) of the hydrogen subsystem is strongly affected by an admixture with a small fraction of helium and occurs at temperatures significantly higher than those of pure hydrogen. At pressures below 150 GPa, the IMT boundary is not related anymore to the H2 subsystem dissociation, the system remains insulating even after the full dissociation of H2 molecules and its transition to an H-He mixture. The offset of the IMT in the H-He mixture relative to the dissociation region in the hydrogen subsystem and the significant reduction of static electrical and thermal conductivity by a factor between two and a few thousand relative to pure hydrogen found in mixtures have consequences for Jupiter and Saturn's thermal evolution, internal structure, and dynamo action, affecting a large fraction of the interior of both planets.
title Direct simulations of H-He mixtures at planetary interior conditions: demixing, insulator-metal transition and miscibility boundaries
topic Earth and Planetary Astrophysics
Materials Science
url https://arxiv.org/abs/2601.23152