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7 Result(s)

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  1. No Access

    Chapter and Conference Paper

    Jacobi-Davidson Algorithm with Fast Matrix-Vector Multiplikation on Massively Parallel and Vector Supercomputers

    The exact diagonalization of very large sparse matrices is a numerical problem common to various fields in science and engineering. We present an advanced eigenvalue alorithm - the so-called Jacobi-Davidson al...

    M. Kinateder, G. Wellein, A. Basermann… in High Performance Computing in Science and … (2001)

  2. No Access

    Article

    Spectral properties of the 2D Holstein polaron

    The two-dimensional Holstein model is studied by means of direct Lanczos diagonalization preserving the full dynamics and quantum nature of phonons. We present numerical exact results for the single-particle s...

    H. Fehske, J. Loos, G. Wellein in Zeitschrift für Physik B Condensed Matter (1997)

  3. No Access

    Article

    Electron correlations and quantum lattice vibrations in strongly coupled electron-phonon systems: A variational slave boson approach

    We investigate the ground-state properties of the two-dimensional Hubbard model with an additional Holstein-type electron-phonon coupling on a square lattice. The effects of quantum lattice vibrations on the s...

    U. Trapper, H. Fehske, M. Deeg, H. Büttner in Zeitschrift für Physik B Condensed Matter (1994)

  4. No Access

    Article

    Dynamic spin and charge susceptibilities in thet−J model

    Based on the spin-rotation-invariant formulation of the Kotliar Ruckenstein slave-boson representation, the paramagnetic spin and charge susceptibilities in thet-J model are calculated. Analyzing the static spin ...

    M. Deeg, H. Fehske, S. Körner, S. Trimper… in Zeitschrift für Physik B Condensed Matter (1994)

  5. No Access

    Article

    Polaron formation and hop** conductivity in the Holstein-Hubbard model

    On the basis of the Holstein-Hubbard model the formation of polarons at finite densities is investigated by means of a variational approach appropriate for describing squeezing and correlation effects. An effe...

    H. Fehske, D. Ihle, J. Loos, U. Trapper… in Zeitschrift für Physik B Condensed Matter (1994)

  6. No Access

    Article

    Slave-boson phase diagram of the two-dimensional extended Hubbard model: Influence of electron-phonon coupling

    We present a detailed study of the extended Hubbard-Peierls model on a square lattice using the slave-boson method proposed by Kotliar and Ruckenstein. The emphasis is on the investigation of the ground state ...

    M. Deeg, H. Fehske, H. Büttner in Zeitschrift für Physik B Condensed Matter (1993)

  7. No Access

    Article

    Slave boson mean field theory for the 2-D Peierls-Hubbard system

    Adapting the Kotliar-Ruckenstein slave boson approach to the Hubbard model with an additional local electronphonon interaction, we have studied the stability of the ground state against (π, π) and (π, 0) Peier...

    M. Deeg, H. Fehske, H. Büttner in Zeitschrift für Physik B Condensed Matter (1992)