Premium
Nearest‐Neighbour Poisson Approximation to a Functional Approach for the Hubbard Model
Author(s) -
Behn U.
Publication year - 1981
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221040121
Subject(s) - hubbard model , poisson distribution , coulomb , born–huang approximation , statistical physics , physics , mathematics , quantum mechanics , condensed matter physics , mathematical analysis , electron , approximation error , statistics , superconductivity
Abstract In the framework of the Poisson approximation to a functional scheme for the Hubbard model the effect of the spatial correlation of the discrete stochastic potential Uv i (t) simulating the spin‐↓ subsystem is considered. For a half‐filled band in the paramagnetic case at zero temperature the density of states is calculated in a nearest‐neighbour approximation. For strong Coulomb repulsion the subbands occur sharper and the minimum in between is deeper compared with the single‐site approximation. The influence of the spatial correlation on the possible appearance of a gap within a dynamic approximation is discussed.