Self-consistent equation-of-motion approach for polarons

Abstract
The polaron problem is treated in a self-consistent manner. The treatment is based on Heisenberg's equations of motion starting from a trial expression for the electron position which includes only one real phonon but any number of virtual phonons. Numerical results for the polaron effective mass and the optical-absorption coefficient are given for electron-LO-phonon coupling strengths ranging from 0 to 4.5. The results are discussed and compared with those obtained by Feynman and by Lee, Low, and Pines.