Tangential and quantum frictional forces on a neutral particle moving   near a surface
  We calculate tangential forces applied to a ground state atom (nanoparticle) moving with nonrelativistic velocity parallel to the surface of Drude -modelled or Lorentz -modelled half -space using the formalism of fluctuation electrodynamics.The obtained formulae assume the nonretarded regime and arbitrary temperatures of the particle and medium. The quantum frictional force is realized at zero temperature of the particle and medium and can reach about 1/3 of the static value of the Casimir -Polder force in the case of ground state atom. In the case of nanoparticles and nonzero temperature, the tangential forces appears to be both frictional and accelerating. Numerical examples are given for atoms of Na above the surface of Au and MgO nanoparticles above the surface of SiC. 
G.V. Dedkov and A.A. Kyasov
cond-mat.other quant-ph