Exact dynamical coarse-graining without time-scale separation

Jianfeng Lu, Eric Vanden-Eijnden

Research output: Contribution to journalArticlepeer-review


A family of collective variables is proposed to perform exact dynamical coarse-graining even in systems without time scale separation. More precisely, it is shown that these variables are not slow in general, yet satisfy an overdamped Langevin equation that statistically preserves the sequence in which any regions in collective variable space are visited and permits to calculate exactly the mean first passage times from any such region to another. The role of the free energy and diffusion coefficient in this overdamped Langevin equation is discussed, along with the way they transform under any change of variable in collective variable space. These results apply both to systems with and without inertia, and they can be generalized to using several collective variables simultaneously. The view they offer on what makes collective variables and reaction coordinates optimal breaks from the standard notion that good collective variable must be slow variable, and it suggests new ways to interpret data from molecular dynamics simulations and experiments.

Original languageEnglish (US)
Article number044109
JournalJournal of Chemical Physics
Issue number4
StatePublished - Jul 28 2014

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


Dive into the research topics of 'Exact dynamical coarse-graining without time-scale separation'. Together they form a unique fingerprint.

Cite this