Fermi liquid behavior in the 2D Hubbard model at low temperatures
The 2D Hubbard model is (probably) the simplest model which involves electron correlations. There remains many open questions about it, and one of them is related to the Fermi liquid or non Fermi liquid behaviour of the model. The main goal of the paper is to study this question, and, loosely speaking, it shows that for chemical potential smaller than two, the weak coupling 2D Hubbard model is a Fermi liquid up to infinitely small temperature and whichever the sign of the interaction. The proof of this result is (very) long, it is the article as the whole, and is based on Grassmann functional integrals, Schwinger function and Renormalization Group which hold on the assumption of smallness and smoothness on some parameters. The latter property is proven by iterative argument.
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