An Analytic Study of the E-e Jahn-Teller Polaron
An analytic study is presented of the E-e Jahn-Teller (JT) polaron. The Hamiltonian is mapped onto a new Hilbert space, which is isomorphic to an eigenspace of the angular momentum operator J, belonging to a fixed eigenvalue j of J. In this representation, the Hamiltonian decomposes into a Holstein term and a residual JT interaction. While the ground state of the JT polaron is shown to belong to j=1/2, the Holstein polaron is obtained for the "unphysical" value j=0. This is the optimal form of the Hamiltonian, which can be achieved by purely analytic means, allowing the JT and the Holstein polaron to be treated in a unified framework. The new Hamiltonian is then subjected to a variational treatment, yielding the dispersion relations and effective masses for both polarons.