9 papers
Evolution of One-Particle and Double-Occupied Green Functions for the Hubbard Model at Half-Filling With Lifetime Effects Within The Moment Approach
S. Schafroth, J. J. Rodríguez-Núñez
We evaluate the one-particle and double-occupied Green functions for the Hubbard model at half-filling using the moment approach of Nolting. Our starting point is a self-energy, $Σ…
Metal-Insulator Transition in the Two-Dimensional Hubbard Model at Half-Filling with Lifetime Effects within the Moment Approach
J. J. Rodríguez-Núñez, S. Schafroth
We explore the effect of the imaginary part of the self-energy, , having a single pole, , with spectral weight, , and quasi-particle lifet…
Self-consistent calculation of particle-hole diagrams on the Matsubara frequency: FLEX approximation
J. J. Rodríguez-Núñez, S. Schafroth
We implement the numerical method of summing Green function diagrams on the Matsubara frequency axis for the fluctuation exchange (FLEX) approximation. Our method has previously be…
Superconducting properties of the attractive Hubbard model
M. H. Pedersen, J. J. Rodriguez-Nunez, H. Beck +2
A self-consistent set of equations for the one-electron self-energy in the ladder approximation is derived for the attractive Hubbard model in the superconducting state. The equati…
Double fluctuations on the attractive Hubbard model: ladder approximation
S. Schafroth, J. J. Rodriguez
We explore, for the first time, the effect of double fluctuations on both the diagonal and off-diagonal self-energy. We use the T-Matrix equations below , developed recently b…
Some Global Properties of the Attractive Hubbard Model in the Superconducting Phase: T-Matrix Approximation in 2D
S. Schafroth, J. J. Rodriguez, H. Beck
We have applied the Fast Fourier transform (FFT), which allows to compute efficiently convolution sums, to solve the set of self-consistent T-matrix equations to get the Green func…