Construction of density operator for a general mean-field Hamiltonian and its application to the models of correlated fermions

Jakub Jedrak

Jagiellonian University, Institute of Physics, Condensed Matter Theory Department, Cracow, Poland

Authors: J. Jedrak, J. Spalek We analyze a class of the mean-field lattice-fermion Hamiltonians and construct the corresponding grand-canonical density operator for such a model system. New terms are introduced, and may be interpreted as local fugacities, molecular fields, etc. The presence of such terms is an unavoidable consequence of the consistent statistical description. Although in some cases (e.g. the Hartree or the Hartree-Fock type of approximations) the presented formalism is redundant, in general (e.g. for a renormalized t-J model) it leads to nontrivial modifications. The case of zero temperature is also briefly analyzed. The paper with the same title and abstract appeared as http://arxiv.org/abs/0804.1376

Back