Exact quantum master equation for a molecular aggregate coupled to a harmonic bath

TL;DR

This paper derives an exact quantum master equation for a molecular aggregate model with electronic and vibrational modes coupled to a harmonic bath, aiding the study of coherent exciton transport and optical responses.

Contribution

It provides the first exact quantum master equation for a molecular aggregate with vibrational modes coupled to a harmonic bath, enabling improved analysis of quantum transport.

Findings

Offers a computational tool for testing quantum transport approximations.

Provides insights into long-lived coherent optical responses in dissipative environments.

Facilitates understanding of exciton dynamics in molecular systems.

Abstract

We consider a molecular aggregate consisting of $N$ identical monomers. Each monomer comprises two electronic levels and a single harmonic mode. The monomers interact with each other via dipole-dipole forces. The monomer vibrational modes are bilinearly coupled to a bath of harmonic oscillators. This is a prototypical model for the description of coherent exciton transport, from quantum dots to photosynthetic antennae. We derive an exact quantum master equation for such systems. Computationally, the master equation may be useful for the testing of various approximations employed in theories of quantum transport. Physically, it offers a plausible explanation of the origins of long-lived coherent optical responses of molecular aggregates in dissipative environments.