Effect of Memory and Active Forces on Transition Path Time Distributions

J Phys Chem B. 2018 Dec 13;122(49):11186-11194. doi: 10.1021/acs.jpcb.8b06379. Epub 2018 Aug 27.

Abstract

An analytical expression is derived for the transition path time distribution for a one-dimensional particle crossing of a parabolic barrier. Two cases are analyzed: (i) a non-Markovian process described by a generalized Langevin equation with a power-law memory kernel and (ii) a Markovian process with a noise violating the fluctuation-dissipation theorem, modeling the stochastic dynamics generated by active forces. In case i, we show that the anomalous dynamics strongly affect the short time behavior of the distributions, but this happens only for very rare events not influencing the overall statistics. At long times the decay is always exponential, in disagreement with a recent study suggesting a stretched exponential decay. In case ii, the active forces do not substantially modify the short time behavior of the distribution but do lead to an overall decrease of the average transition path time. These findings offer some novel insights, useful for the analysis of experiments of transition path times in (bio)molecular systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Markov Chains
  • Models, Theoretical*
  • Physical Phenomena*
  • Time