Quasi-particle characteristics of the one-dimensional polaron
Abstract
Description
The main quasi-particle characteristics of the one-dimensional polaron are estimated within and beyond the most general Gaussian approximation at arbitrary electron-phonon coupling. We have derived explicitly the ground-state energy and the effective mass in the weak- and strong-coupling regimes. For arbitrary coupling, the Gaussian leading-order term of the polaron self energy improves the corresponding Feynman estimate and represents the lowest upper bound available. We have calculated the next non-Gaussian corrections. Taking into account systematically higher-order corrections does not perturb considerably the obtained results.
REVTeX, 13 pages, 1 figure in a separate "fig1.ps" file, 2 tables
REVTeX, 13 pages, 1 figure in a separate "fig1.ps" file, 2 tables