Dephasing in an atom

Abstract

When an atom in vacuum is near a surface of a dielectric the energy of a fluctuating electromagnetic field depends on a distance between them resulting, as known, in the force called van der Waals one. Besides this fluctuation phenomenon there is one associated with formation of a mean electric field which is equivalent to an order parameter. In this case atomic electrons are localized within atomic distances close to the atom and the total ground state energy is larger, compared to the bare atom, due to a polarization of the dielectric and a creation of a mean electric field locally distributed in the dielectric. The phenomenon strongly differs from the usual ferroelectricity and has a pure quantum origin connected with a violation of the interference due to dephasing of fluctuating electron states in the atom.