Dresden 2020 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 40: Data Analytics, Extreme Events, and Nonlinear Stochastic Systems (joint session DY/SOE)

DY 40.8: Talk

Wednesday, March 18, 2020, 17:15–17:30, ZEU 118

Non-Markovian barrier crossing with two-time-scale memory is dominated by the faster memory component — •Julian Kappler, Victor B. Hinrichsen, and Roland R. Netz — Freie Universität Berlin, Fachbereich Physik, Berlin, Germany

We investigate non-Markovian barrier-crossing kinetics of a massive particle in one dimension in the presence of a memory function that is the sum of two exponentials with different memory times. Our Langevin simulations for the special case where both exponentials contribute equally to the total friction show that the barrier-crossing time becomes independent of the longer memory time if at least one of the two memory times is larger than the intrinsic diffusion time. When we associate memory effects with coupled degrees of freedom that are orthogonal to a one-dimensional reaction coordinate, this counterintuitive result shows that the faster orthogonal degrees of freedom dominate barrier-crossing kinetics in the non-Markovian limit and that the slower orthogonal degrees become negligible, quite contrary to the standard time-scale separation assumption. We construct a crossover formula for the barrier crossing time that is valid for general multi-exponential memory kernels. This formula can be used to estimate barrier-crossing times for general memory functions for high friction, i.e. in the overdamped regime, as well as for low friction, i.e. in the inertial regime.