Absence of crystallization in metallic hydrogen

It is argued that, because of the differing roles of electronic screening in solid and fluid states, metallic hydrogen will remain a fluid at all pressures. In the solid state the static interaction between localized protons is reduced by electronic screening, and this leads to a reduction in the magnitude of proton-configuration-dependent part of the energy. In the fluid state, in which we have both a proton gas and an electron gas, the electronic contribution to screening plays no role since the lower-kinetic-energy protons are much more polarizable. The net result is for screening of the proton-proton interaction to favor the fluid state and estimates are presented which indicate that the effect is sufficient to prevent crystallization at any density. Results are also presented for some quasiparticle properties of the proton fluid.