Dissipative Quantum Transport in Macromolecules: An Effective Field Theory Approach

TL;DR

This paper develops an atomistic, effective field theory approach using path integrals to analyze dissipative quantum transport in macromolecules, enabling analytical computation of quantum coherence loss.

Contribution

It introduces a novel field-theoretic framework that simplifies the analysis of quantum dynamics in macromolecular systems by avoiding Keldysh contours.

Findings

Analytical derivation of quantum excitation dynamics

Application to coherence loss in polymer systems

Effective description consistent with fluctuation-dissipation

Abstract

We introduce an atomistic approach to the dissipative quantum dynamics of charged or neutral excitations propagating through macromolecular systems. Using the Feynman-Vernon path integral formalism, we analytically trace out from the density matrix the atomic coordinates and the heat bath degrees of freedom. This way we obtain an effective field theory which describes the real-time evolution of the quantum excitation and is fully consistent with the fluctuation-dissipation relation. The main advantage of the field-theoretic approach is that it allows to avoid using the Keldysh contour formulation. This simplification makes it straightforward to derive Feynman diagrams to analytically compute the effects of the interaction of the propagating quantum excitation with the heat bath and with the molecular atomic vibrations. For illustration purposes, we apply this formalism to investigate the loss of quantum coherence of holes propagating through a poly(3-alkylthiophene) polymer