The Anharmonic Electron-Phonon Problem.

The anharmonic electron-phonon problem is solved in the infinite-dimensional limit using quantum Monte Carlo simulation. Charge-density-wave order is seen to remain at half filling even though the anharmonicity removes the particle-hole symmetry of the model. Superconductivity is strongly favored away from half filling but the anharmonicity does not enhance transition temperatures over the maximal values found in the harmonic limit. {copyright} {ital 1996 The American Physical Society.}