Information Thermodynamics of the Transition-Path Ensemble

TL;DR

This paper introduces an information-theoretic framework for understanding the reaction coordinate in chemical transitions, linking entropy production to the information gained about reactivity, and highlighting the committor's optimality.

Contribution

It develops a novel information-theoretic approach to the reaction coordinate, establishing a fundamental link between entropy production and dynamical information in transition-path theory.

Findings

Entropy production equals information about reactivity for transition paths.

The committor maximizes relevance as a reaction coordinate.

The framework applies at the level of individual coordinates.

Abstract

The reaction coordinate describing a transition between reactant and product is a fundamental concept in the theory of chemical reactions. Within transition-path theory, a quantitative definition of the reaction coordinate is found in the committor, which is the probability that a trajectory initiated from a given microstate first reaches the product before the reactant. Here we develop an information-theoretic origin for the committor and show how selecting transition paths from the equilibrium ensemble induces entropy production which exactly equals the information that system dynamics provide about the reactivity of trajectories. This equality of entropy production and dynamical information generation also holds at the level of arbitrary individual coordinates, providing parallel measures of the coordinate's relevance to the reaction, each of which is maximized by the committor.