Electromagnetic vacuum of complex media. II. Lamb shift and total vacuum energy

摘要: We study the physical content of electromagnetic vacuum energy a random medium made atomic electric dipoles. First, we evaluate contribution statistical fluctuations to average total energy, which is out integration variations Lamb shift with respect coupling constant. While function electrical susceptibility only, generally not. Second, make clear why effective bulk does not account for molecular dielectric. Consequently, derive from except at leading order in density. The local field factors provide natural cutoffs spectrum wavelength correlation length. Third, investigate what extent shifts dielectric constant may be attributed binding In particular, continuum approximation have found relation between electrostatic and Lorentz-Lorenz shift. Nonetheless, conclude that knowledge refractive index insufficient either quantify radiative modes or estimate clusters.