Hamiltonian Flow in Condensed Matter Physics
A recently developed method to diagonalize or block-diagonalize Hamiltoni-ans by means of an appropriate continuous unitary transformation is reviewed. Two applications in condensed matter physics are given as examples: (i) the interaction of an n-orbital model of fermions in the limit of large n is brought to block-diagonal form, and (ii) the generation of the effective attractive two-electron interaction due to the elimination of electron-phonon interaction is given. The advantage of this method in particular in comparison to conventional perturbation theory is pointed out.
KeywordsOccupation Number Diagonal Part Diagonal Matrix Element HAMILTONIAN Flow Matrix Element Versus
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