Diffusion in periodic potentials with path integral hyperdynamics

T. Ikonen, M.D. Khandkar, L.Y. Chen, S.C. Ying, T. Ala-Nissila

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
18 Downloads (Pure)

Abstract

We consider the diffusion of Brownian particles in one-dimensional periodic potentials as a test bench for the recently proposed stochastic path integral hyperdynamics (PIHD) scheme [Chen and Horing, J. Chem. Phys. 126, 224103 (2007)]. First, we consider the case where PIHD is used to enhance the transition rate of activated rare events. To this end, we study the diffusion of a single Brownian particle moving in a spatially periodic potential in the high-friction limit at low temperature. We demonstrate that the boost factor as compared to straight molecular dynamics (MD) has nontrivial behavior as a function of the bias force. Instead of growing monotonically with the bias, the boost attains an optimal maximum value due to increased error in the finite path sampling induced by the bias. We also observe that the PIHD method can be sensitive to the choice of numerical integration algorithm. As the second case, we consider parallel resampling of multiple bias force values in the case of a Brownian particle in a periodic potential subject to an external ac driving force. We confirm that there is no stochastic resonance in this system. However, while the PIHD method allows one to obtain data for multiple values of the ac bias, the boost with respect to MD remains modest due to the simplicity of the equation of motion in this case.
Original languageEnglish
Article number026703
Pages (from-to)1-7
JournalPhysical Review E
Volume84
Issue number2
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed

Keywords

  • Brownian motion
  • diffusion
  • hyperdynamics
  • Langevin dynamics
  • path integral
  • rare events

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