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Renormalization approach to many-particle systems

K. W. Becker·A. Huebsch·T. Sommer
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Abstract

This paper presents a renormalization approach to many-particle systems. By starting from a bare Hamiltonian ${\cal H}= {\cal H}_0 +{\cal H}_1$ with an unperturbed part ${\cal H}_0$ and a perturbation ${\cal H}_1$,we define an effective Hamiltonian which has a band-diagonal shape with respect to the eigenbasis of ${\cal H}_0$. This means that all transition matrix elements are suppressed which have energy differences larger than a given cutoff $λ$ that is smaller than the cutoff $Λ$ of the original Hamiltonian. This property resembles a recent flow equation approach on the basis of continuous unitary transformations. For demonstration of the method we discuss an exact solvable model, as well as the Anderson-lattice model where the well-known quasiparticle behavior of heavy fermions is derived.

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K. W. Becker, A. Huebsch, T. Sommer. 2002-11-11. Renormalization approach to many-particle systems. https://doi.org/10.1103/physrevb.66.235115

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