28 research outputs found
Time dependent current in a nonstationary environment: A microscopic approach
Based on a microscopic system reservoir model,where the associated bath is
not in thermal equilibrium, we simulate the nonstationary Langevin dynamics and
obtained the generalized nonstationary fluctuation dissipation relation (FDR)
which asymptotically reduces to the traditional form. Our Langevin dynamics
incorporates non-Markovian process also, the origin of which lies on the
decaying term of the nonstationary FDR. We then follow the stochastic dynamics
of the Langevin particle based on the Fokker-Planck-Smoluchowski description,
in ratchet potential to obtain the steady and time dependent current in an
analytic form. We also examine the influence of initial excitation and
subsequent relaxation of bath modes on the transport of the Langevin particle
to show that the nonequilibrium nature of the bath leads to both strong
non-exponential dynamics as well as nonstationary current.Comment: 10 pages, RevTex4, references updated, final version to appear in
Journal of Mathematical Physic