  One of the major theoretical methods in understanding polymer translocation
through a nanopore is the Fokker-Planck formalism based on the assumption of
quasi-equilibrium of polymer conformations. The criterion for applicability of
the quasi-equilibrium approximation for polymer translocation is that the
average translocation time per Kuhn segment, $\langle \tau \rangle/N_K$ is
longer than the relaxation time $\tau_0$ of the polymer. Towards an
understanding of conditions that would satisfy this criterion, we have
performed coarse-grained three dimensional Langevin dynamics and multi-particle
collision dynamics simulations. We have studied the role of initial
conformations of a polyelectrolyte chain (which were artificially generated
with a flow field) on the kinetics of its translocation across a nanopore under
the action of an externally applied transmembrane voltage $V$ (in the absence
of the initial flow field). Stretched (out-of-equilibrium) polyelectrolyte
chain conformations are deliberately and systematically generated and used as
initial conformations in translocation simulations. Independent simulations are
performed to study the relaxation behavior of these stretched chains and a
comparison is made between the relaxation timescale and the mean translocation
time ($\langle \tau \rangle$). For such artificially stretched initial states,
$\langle \tau \rangle/N_K < \tau_0$, demonstrating the inapplicability of the
quasi-equilibrium approximation. Nevertheless, we observe a scaling of $\langle
\tau \rangle \sim 1/V$ over the entire range of chain stretching studied, in
agreement with the predictions of the Fokker-Planck model. On the other hand,
for realistic situations where initial artificially imposed flow field is
absent, a comparison of experimental data reported in the literature with the
theory
