Quantum equilibration of a model system Porphine

TL;DR

This paper demonstrates rapid quantum equilibration in a molecular model of porphine, showing that even small systems can reach a stable state quickly after laser-induced excitation.

Contribution

It provides the first numerical evidence of fast quantum equilibration in a molecular system, extending the understanding beyond large many-body systems.

Findings

Equilibration occurs within approximately 200 femtoseconds.

Rapid equilibration is observed for initial states induced by laser pulses.

The study confirms that small quantum systems can exhibit equilibration behavior.

Abstract

There is a renewed interest in the derivation of statistical mechanics from the dynamics of closed quantum systems. A central part of this program is to understand how far-from-equilibrium closed quantum system can behave as if relaxing to a stable equilibrium. Equilibration dynamics has been traditionally studied with a focus on the so-called quenches of large-scale many-body systems. Alternatively, we consider here the equilibration of a molecular model system describing the double proton transfer reaction in porphine. Using numerical simulations, we show that equilibration in this context indeed takes place and does so very rapidly ($\sim \!\! 200$fs) for initial states induced by pump-dump laser pulse control with energies well above the synchronous tunneling barrier.