A correlated-polaron electronic propagator: Open electronic dynamics beyond the Born-Oppenheimer approximation

Abstract

In this work, we develop an approach to treat correlated many-electron dynamics, dressed by the presence of a finite-temperature harmonic bath. Our theory combines a small polaron transformation with the second-order time-convolutionless master equation and includes both electronic and system-bath correlations on equal footing. Our theory is based on the ab initio Hamiltonian, and is thus well-defined apart from any phenomenological choice of basis states or electronic system-bath coupling model. The equation-of-motion for the density matrix we derive includes non-Markovian and non-perturbative bath effects and can be used to simulate environmentally broadened electronic spectra and dissipative dynamics, which are subjects of recent interest. The theory also goes beyond the adiabatic Born-Oppenheimer approximation, but with computational cost scaling such as the Born-Oppenheimer approach. Example propagations with a developmental code are performed, demonstrating the treatment of electron-correlation in absorption spectra, vibronic structure, and decay in an open system. An untransformed version of the theory is also presented to treat more general baths and larger systems.

Strongly Coupled Quantum Heat Machines

“…The validity of the "weak" coupling assumption for the spectrum G 1 (ω) has been broadly shown. 6,9,26,32,37,40,56 In a similar manner, the operator A ± (t), will constraint G 2 (ω) to the weak coupling regime as long as 31,36 which implies that the rate between absorption and emission processes is equal to a Boltzmann factor, with the bath temperature, which is independent of the frequency. …”

Optimal power generation using dark states in dimers strongly coupled to their environment

“…where m = A, E for absorption and emission, and the angle χ is defined by (17a) and (17b). In (27), w G m ( ) j are the rates for the phonon-renormalized electronic transitions of monomer-j and w G m ( ) 12 are the contributions to the rates due to the collective effects of the monomers in the dimer. Therefore, recalling the definition of the -ñ | (16b), the first two terms in (27) are seen to describe the contribution from each monomer independently.…”

“…We treat the strong coupling by using a polaron transformation [22]. Energy transfer in the polaron frame has been studied before [22][23][24][25][26][27], but not in the context of dark state protection. We will show that strong coupling has a profound effect on quantum interference processes such that it no longer necessarily improves the efficiency of devices.…”

Dynamics of polaron formation in Li2O2from density functional perturbation theory

“…However, this is an active area of research that is rapidly progressing. Recently, a first-principles approach for capturing polarons beyond the Born-Oppenheimer approximation was proposed, 33 where The red balls represent the oxygen atoms and green balls represent the lithium atoms. The injected electron is delocalized, forming a Bloch wave, and the atomic structure of Li 2 O 2 crystal remains unaltered.…”