  There are three regimes in the theory of energy absorption: The adiabatic
regime, the linear-response (Kubo) regime, and the non-perturbative regime. The
mesoscopic Drude formula for electrical conductance, and the wall formula for
friction, can be regarded as special cases of the general formulation of the
dissipation problem. The overview is based on a research report for 1998-2000.
