Quantum Diffusive Dynamics of Macromolecular Transitions

TL;DR

This paper introduces a quantum-corrected extension of the Dominant Reaction Pathways formalism to study how quantum fluctuations influence macro-molecular transition dynamics, revealing significant modifications in reaction mechanisms.

Contribution

The authors develop a quantum-enhanced DRP method incorporating quantum corrections to classical Langevin dynamics, applied to peptide transitions.

Findings

Quantum fluctuations can reduce energy barriers by up to 50%.

The method aligns with instanton theory in simple cases.

Quantum effects significantly alter peptide reaction pathways.

Abstract

We study the role of quantum fluctuations of atomic nuclei in the real-time dynamics of non-equilibrium macro-molecular transitions. To this goal we introduce an extension of the Dominant Reaction Pathways (DRP) formalism, in which the quantum corrections to the classical overdamped Langevin dynamics are rigorously taken into account to order h^2 . We first illustrate our approach in simple cases, and compare with the results of the instanton theory. Then we apply our method to study the C7_eq to C7_ax transition of alanine dipeptide. We find that the inclusion of quantum fluctuations can significantly modify the reaction mechanism for peptides. For example, the energy difference which is overcome along the most probable pathway is reduced by as much as 50%.