17 research outputs found
Content-based image retrieval based on colour histogram and the discrete cosine transform
We study the static screening in a Hubbard-like model using fixed-node
diffusion Monte Carlo. We find that the random phase approximation is
surprisingly accurate even for metallic systems close to the Mott transition.
As a specific application we discuss the implications of the efficient
screening for the superconductivity in the doped Fullerenes. In the Monte Carlo
calculations we use trial functions with two Gutzwiller-type parameters. To
deal with such trial functions, we introduce a method for efficiently
optimizing the Gutzwiller parameters, both in variational and in fixed-node
diffusion Monte Carlo.Comment: 4 pages LaTeX with 4 eps figures; Computer Simulations Studies in
Condensed Matter Physics XII, Eds.: D.P. Landau, S.P. Lewis, and H.B.
Schuettler, Springer 1999; additional material available at
http://www.mpi-stuttgart.mpg.de/docs/ANDERSEN/fullerene