Theory of dense hydrogen: Proton pairing

Abstract

Dense hydrogen, a dual Fermion system, possesses a Hamiltonian of high symmetry and especial simplicity. As a consequence of the latter its ground state energy satisfies general scaling conditions, independent of phase. Electron exchange is an important contributor, and its role in proton pairing (so evident at low densities) can be argued as a persistent feature. In the single particle description instabilities associated with band-gap closure can be seen as incipient charge density waves but in pair coordinates. This gives rise to a notion of higher pairing within which there can be an associated broken symmetry in electron density (consistent with the observed infrared activity). The persistence of exchange driven pairing under conditions where temperatures approach characteristic vibron energies is discussed in the context of recent reports of the metallization of hydrogen by dynamic methods.