  In systems far from equilibrium, the fluctuation-dissipation relation is
violated due to the lack of detailed balance. Recently, for a class of Langevin
equations, it has been proved that this violation is related to energy
dissipation as an equality [T. Harada and S. Sasa, Phys. Rev. Lett., in press;
cond-mat/0502505]. We provide a microscopic description of this equality by
studying a non-equilibrium colloidal system on the basis of classical mechanics
with some physical assumptions.
