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arXiv · 1003.1867

Ward identities for the Anderson impurity model: derivation via functional methods and the exact renormalization group

Peter Kopietz·Lorenz Bartosch·Lucio Costa·Aldo Isidori·Alvaro Ferraz
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Abstract

Using functional methods and the exact renormalization group we derive Ward identities for the Anderson impurity model. In particular, we present a non-perturbative proof of the Yamada-Yosida identities relating certain coefficients in the low-energy expansion of the self-energy to thermodynamic particle number and spin susceptibilities of the impurity. Our proof underlines the relation of the Yamada-Yosida identities to the U(1) x U(1) symmetry associated with particle number and spin conservation in a magnetic field.

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Peter Kopietz, Lorenz Bartosch, Lucio Costa, Aldo Isidori, Alvaro Ferraz. 2010-03-09. Ward identities for the Anderson impurity model: derivation via functional methods and the exact renormalization group. https://doi.org/10.1088/1751-8113/43/38/385004

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