Theory of superconductivity based on direct electron-phonon coupling. II

The origin of a superconducting interaction in metallic hydrogen computed in the preceding paper is shown to be an electronic screening of the zero-point oscillations of the nuclei as a result of electron-phonon interaction, where the superconducting wave function allows more effective screening than the normal-state wave function. Virtual phonons are involved in the screening process, and the phonons of interest are the bare longitudinal phonons with small wave vector. The screening results in a correlation energy between electrons and nuclei where the correlation is of long range. The screening length is shown to be the same as the coherence length defined by the uncertainty principle.