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Flow Equations and Normal Ordering. A Survey

Franz Wegner
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Abstract

First we give an introduction to the method of diagonalizing or block-diagonalizing continuously a Hamiltonian and explain how this procedure can be used to analyze the two-dimensional Hubbard model. Then we give a short survey on applications of this flow equation on other models. Finally we outline, how symmetry breaking can be introduced by means of a symmetry breaking of the normal ordering, not of the Hamiltonian.

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Franz Wegner. 2005-11-28. Flow Equations and Normal Ordering. A Survey. https://doi.org/10.1088/0305-4470%2F39%2F25%2Fs29

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