Fermi-liquid-to-polaron crossover .2. Double exchange and the physics of colossal magnetoresistance

We use the dynamical mean-field method to study a model of electrons Jahn-Teller coupled to localized classical oscillators and ferromagnetically coupled to ''core spins.'' The model, we argue, contains the essential physics of the ''colossal magnetoresistance'' manganites Re(1-x)A(x)MnO(3). We determine the different regimes of the model and present results for the temperature and frequency dependence of the conductivity, the electron spectral function, and the root-mean-square lattice parameter fluctuations. We compare our results to data and give a qualitative discussion of important physics not included in the calculation. Extensive use is made of results from a companion paper.