  In this work we develop a theory of correlated many-electron dynamics dressed
by the presence of a finite-temperature harmonic bath. The theory is based on
the ab-initio Hamiltonian, and thus well-defined apart from any
phenomenological choice of collective basis states or electronic coupling
model. The equation-of-motion includes some bath effects non-perturbatively,
and can be used to simulate line- shapes beyond the Markovian approximation and
open electronic dynamics which are subjects of renewed recent interest. Energy
conversion and transport depend critically on the ratio of electron-electron
coupling to bath-electron coupling, which is a fitted parameter if a
phenomenological basis of many-electron states is used to develop an electronic
equation of motion. Since the present work doesn't appeal to any such basis, it
avoids this ambiguity. The new theory produces a level of detail beyond the
adiabatic Born-Oppenheimer states, but with cost scaling like the
Born-Oppenheimer approach. While developing this model we have also applied the
time-convolutionless perturbation theory to correlated molecular excitations
for the first time. Resonant response properties are given by the formalism
without phenomenological parameters. Example propagations with a developmental
code are given demonstrating the treatment of electron-correlation in
absorption spectra, vibronic structure, and decay in an open system.

Quantum Physics;Other Condensed Matter;Chemical Physics