  The impact of thermal fluctuations on the translocation dynamics of a polymer
chain driven through a narrow pore has been investigated theoretically and by
means of extensive Molecular-Dynamics (MD) simulation. The theoretical
consideration is based on the so-called velocity Langevin (V-Langevin) equation
which determines the progress of the translocation in terms of the number of
polymer segments, $s(t)$, that have passed through the pore at time $t$ due to
a driving force $f$. The formalism is based only on the assumption that, due to
thermal fluctuations, the translocation velocity $v=\dot{s}(t)$ is a Gaussian
random process as suggested by our MD data. With this in mind we have derived
the corresponding Fokker-Planck equation (FPE) which has a nonlinear drift term
and diffusion term with a {\em time-dependent} diffusion coefficient $D(t)$.
Our MD simulation reveals that the driven translocation process follows a {\em
super}diffusive law with a running diffusion coefficient $D(t) \propto
t^{\gamma}$ where $\gamma < 1$. This finding is then used in the numerical
solution of the FPE which yields an important result: for comparatively small
driving forces fluctuations facilitate the translocation dynamics. As a
consequence, the exponent $\alpha$ which describes the scaling of the mean
translocation time $<\tau>$ with the length $N$ of the polymer, $<\tau> \propto
N^{\alpha}$ is found to diminish. Thus, taking thermal fluctuations into
account, one can explain the systematic discrepancy between theoretically
predicted duration of a driven translocation process, considered usually as a
deterministic event, and measurements in computer simulations. In the
non-driven case, $f=0$, the translocation is slightly subdiffusive and can be
treated within the framework of fractional Brownian motion (fBm).
