Exact Transport Parameters for Driving Forces of Arbitrary Magnitude

Abstract
A straightforward analysis of the time-correlation function of interest in response theory involves the entire complicated solution of the dynamical problem. Using projection techniques we derive a simpler equation obeyed by the time-correlation function. Laplace transforms are used to solve this equation for the case when the driving force is a step function of arbitrary magnitude. The results are independent of the near-origin approximation of the Kubo formalism.