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 second order in h-bar . We first illustrate our approach with a simple toy model and then we apply it 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 example, the energy difference which is overcome along the most probable pathway is reduced by as much as 50\%.
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\%.
R
second order in h-bar
order h^2
R
with a simple toy model and then we apply it
in simple cases, and compare with the results of the instanton theory. Then we apply our method
R
_{eq
_eq
R
_{ax
_ax
A
for peptides