All-coupling polaron optical response: Analytic approaches beyond the adiabatic approximation

All-coupling theory for the Fröhlich polaron

The Fröhlich model describes the interaction of a mobile impurity with a surrounding bath of phonons which leads to the formation of a quasiparticle, the polaron. In this paper an efficient renormalization group approach is presented which provides a description of Fröhlich polarons in all regimes ranging from weak to strong coupling. The extended renormalization group approach introduced here ...

Optical response of many-polaron systems

Exact results for the density of states and the ac conductivity of the spinless Holstein model at finite carrier density are obtained combining Lanczos and kernel polynomial methods.

Appearance of Gauge Fields and Forces beyond the adiabatic approximation

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

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-...

Adiabatic approximation of time-dependent density matrix functional response theory.

Time-dependent density matrix functional theory can be formulated in terms of coupled-perturbed response equations, in which a coupling matrix K(omega) features, analogous to the well-known time-dependent density functional theory (TDDFT) case. An adiabatic approximation is needed to solve these equations, but the adiabatic approximation is much more critical since there is not a good "zero ord...