Dynamics of Unbiased Translocation
Although most examples of translocation involve a driving force of some kind, the unbiased process presents an interesting
system itself and a thorough description of the dynamics of this process are useful to understand the driven case.
In the absence of a driving mechansim, the dynamics of translocation essentially amount to diffusion over the entropic barrier
intrinsic to crossing the membrane.
To study this system, we employ two different approaches.
First, we have developed a simple model of translocation as a single random walker traversing the entropic barrier.
With this model, the dynamics can be studied by both direct Monte Carlo simulations as well as the exact numerical approach
to gain insight into the dyanmics of the "ideal" translocation process.
From this work, we have uncovered interesting features of the entropic barrier and the impact of differing boundary conditions
Extending to a more realistic model,
we also perform extensive Langevin Dynamics simulations of trasnlocation with the Espresso simulations package.
With this approach, we have demonstrated that the scaling laws are sensitive to the details of the simulation setup
LINK PAPER - a result which may help resolve disagreement between reported values.
Additionally, we have developed novel measuresments to characterize memory effects in the system
to probe the viscosity dependent scaling laws.
Finally, presenting a new way to quantify the translocaiton process,
we have shown that while the scaling of the total translocation time with polymer length varies with simulation details,
a characterization of the steps of the process agrees with theoretical predictions.
From this work, we have developed a model of translocation as the diffusion of a local minimum.