We investigate the effect of strong electron-electron repulsion on the electronphonon interaction from a Fermi-liquid point of view. In particular we show that the strong interaction is responsible for vertex corrections, which are strongly dependent on the vF q/ω ratio, where vF is the Fermi velocity and q and ω are the transferred momentum and frequency respectively. These corrections generic...

The temperature dependence of the phonon spectra of a-uranium has recently been measured by inelastic neutron scattering and inelastic X-ray scattering. Although there is little evidence of any anharmonicity, the phonon shows some softening in the optic modes at the zone boundary. Furthermore, an extra mode forms at high temperatures, which is incompatible with a structure composed of a monocli...

We have used an exact diagonalization technique to study the stability of the t − J-Holstein and Hubbard-Holstein models under the influence of the electron-phonon interaction. Previous results have been obtained using frozen-phonon technique or introducing only a few dynamical phonon modes due to the large Hilbert space. To check these results we have done exact diagonalization in a small clus...

Methods for quantifying environmentally induced decoherence in quantum systems are investigated. We formulate criteria for measuring the degree of decoherence and consider several representative examples, including a spin interacting with the modes of a bosonic, e.g., phonon, bath. We formulate an approach based on the operator norm measuring the deviation of the actual density matrix from the ...

Methods for quantifying environmentally induced decoherence in quantum systems are investigated. We formulate criteria for measuring the degree of decoherence and consider several representative examples, including a spin interacting with the modes of a bosonic, e.g., phonon, bath. We formulate an approach based on the operator norm measuring the deviation of the actual density matrix from the ...

The many-body ground state of a very general class of electron-phonon Hamiltonians is proven to contain a spin singlet (for an even number of electrons on a nite lattice). The phonons interact with the electronic system in two diierent ways|there is an interaction with the local electronic charge and there is a functional dependence of the electronic hopping Hamiltonian on the phonon coordinate...