Navegação Ciências Exatas e da Terra por Assunto "Fisica teorica da materia condensada"

Resultados 1-6 de 6

    • Aggregation of magnetic microspheres : experiments and simulation 

      Helgesen, G.; Skjeltorp, A.T.; Mors, Paulo Machado; Botet, Robert; Jullien, Remi (1988) [Artigo de periódico]
      Uniformly sized microspheres interacting via long-range magnetic dipolar forces are used to study diffusion-limited cluster aggregation in a plane. The results show that it is possible to scale the temporal evolution of ...

    • Effect of band filling in the Kondo lattice : a mean-field approach 

      Ruppenthal, Alaor Ricardo; Iglesias, Jose Roberto; Gusmao, Miguel Angelo Cavalheiro (1999) [Artigo de periódico]
      The usual Kondo lattice, including an antiferromagnetic exchange interaction between nearest-neighboring localized spins, is treated here in a mean-field scheme that introduces two mean-field parameters: one associated ...

    • Eletronic and phonomic states of the Holstein-Hubbard dimer of variable length 

      Acquarone, C.; Iglesias, Jose Roberto; Gusmao, Miguel Angelo Cavalheiro; Noce, A.; Romano, Alfonso (1998) [Artigo de periódico]
      We consider a model Hamiltonian for a dimer of length a including all the electronic one- and two-body terms consistent with a single orbital per site, a free Einstein phonon term for a frequency V, and an electronphonon ...

    • Fluctuation conductivity of inhomogeneous superconductors : a fractal aggregation model 

      Gusmao, Miguel Angelo Cavalheiro; Mors, Paulo Machado (1990) [Artigo de periódico]
      Numerical simulations of diffusion processes are performed on fractal aggregates designed to mimic the structure of inhomogeneous granular superconductors. The spectral dimensions obtained yield ftuctuation-conductivity ...

    • Magnetic susceptibility and specific heat of the anderson lattice : perturbative expansion around the atomic limit 

      Brunnet, Leonardo Gregory; Gusmao, Miguel Angelo Cavalheiro; Iglesias, Jose Roberto (1992) [Artigo de periódico]
      The Green's functions relevant to the periodic Anderson Hamiltonian are calculated via perturbation theory around the atomic limit. The approximation reproduces exact results in three different limits: zero bandwidth, zero ...

    • Statistical thermodinamics of a two-dimensional cellular system 

      Iglesias, Jose Roberto; Almeida, Rita Maria Cunha de (1991) [Artigo de periódico]
      The principies of statistical physics are applied to the study of cellular systems. Cells that fill a flat surface are characterized by area, perimeter, and number of sides. A set of constraints is established, taking into ...