  Problems in the Lifshitz theory of atom-wall interaction arise when the dc
conductivity of dielectric wall is included into the model of the dielectric
response. We review the low-temperature behavior of the free energy and entropy
of dispersion interaction for both dielectric and metallic walls. Consistency
of the obtained results with thermodynamics and experimental data is analyzed.
Recent attempts to include the screening effects and diffusion currents into
the Lifshitz theory are considered. It is shown that this leads to the
violation of the Nernst heat theorem for wide classes of wall materials. The
physical reasons for the emergence of thermodynamic and experimental
inconsistencies are elucidated.
