Low Temperature Physics: 45, 294 (2019); https://doi.org/10.1063/1.5090043
Fizika Nizkikh Temperatur: Volume 45, Number 3 (March 2019), p. 338-341    ( to contents , go back )

Dense quantum hydrogen

W.J. Nellis

Department of Physics, Harvard University, Cambridge, MA 02138, USA
E-mail: nellis@fas.harvard.edu

Received October 24, 2018

Abstract

Ultracondensed fluid metallic hydrogen has been made at high pressures. Solid metallic H would have several scientific and technological applications if metallic fluid hydrogen made at high pressures could be quenched metastably to a solid at ambient. The quantum nature of dense hydrogen is an issue both at high pressures and in materials recovered metastably on release of pressure. Quantum zero point vibrations of H might have a significant affect on properties of metallic H at high pressures and might adversely affect lifetimes of metastable solid hydrogen, which is particularly relevant for applications. Metallic (degenerate) fluid H has been made at finite temperatures with a reverberating shock wave under dynamic compressions and under static compressions in laser-heated diamond-anvil cells. The pressure-temperature (P–T) regime in those experiments ranged up to 180 GPa and 3000 K, in which metallic fluid H is a quantum-degenerate fluid with T/TF << 1, where TF is Fermi temperature. The lifetime of an experiment under static compression near 500 GPa at 5.5 K ranged up to weeks, sufficiently long to warrant concern about quantum diffusion having a major affect on the chemical composition of that metallic sample.

Key words: ultracondensed metallic fluid, metallic hydrogen, high pressure.

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