Limits of the dynamical approach to the nonlinear response of mesoscopic systems - art. no. 045310

We have considered the nonlinear response of mesoscopic systems of noninter acting electrons to the time-dependent external field. In this consideratio n the inelastic processes have been neglected and the electron thermalizati on occurs due to the electron exchange with the reservoirs. We have demonst rated that the diagrammatic technique based on the method of analytical con tinuation or on the Keldysh formalism is capable of describing the heating automatically. The corresponding diagrams contain loose diffusons. We have shown the equivalence of such a diagrammatic technique to the solution to t he kinetic equation for the electron-energy distribution function. We have identified two classes of problems with different behavior under ac pumping . In one class of problems (persistent current fluctuations, Kubo conductan ce) the observable depends on the electron-energy distribution renormalized by heating. In another class of problems (Landauer conductance) the observ able is insensitive to heating and depends on the temperature of electron r eservoirs. As examples of such problems we have considered in detail the pe rsistent current fluctuations under ac pumping and two types of conductance measurements (Landauer conductance and Kubo, conductance) that behave diff erently under ac pumping. We also foumulate two types of time-dependent ran dom-matrix theories that apply in the ergodic regime for the adiabatic and high-frequency pumping, respectively.