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On the Connection between Electric and Magnetic Properties of the Hubbard Model I. Electrical Conductivity
Author(s) -
Nolting W.
Publication year - 1975
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.2220700209
Subject(s) - ansatz , electrical resistivity and conductivity , conductivity , tensor (intrinsic definition) , connection (principal bundle) , limiting , condensed matter physics , hubbard model , physics , mathematics , mathematical analysis , quantum electrodynamics , quantum mechanics , pure mathematics , geometry , mechanical engineering , superconductivity , engineering
An approximate expression for the electrical conductivity σ is derived by means of the method of spectral moments. Therefore, σ is written in terms of a spectral density, for which a suitable ansatz is chosen. Free parameters of this ansatz are fixed by equating moments. The so obtained approximate solution of the conductivity tensor fulfils the well‐known sum rules and contains nearly all exactly calculable limiting cases. Furthermore, Moneckes statement that the conductivity exhibits free acceleration behaviour even in the case of strong electronic correlations, is shown to be incorrect.