  A new theory describing the interaction between atoms and a conductor with
small densities of current carriers is presented. The theory takes into account
the penetration of the static component of the thermally fluctuating field in
the conductor and generalizes the Lifshitz theory in the presence of a spatial
dispersion. The equation obtained for the force describes the continuous
crossover between the Lifshitz results for dielectrics and metals.

Other Condensed Matter;Statistical Mechanics;Quantum Physics