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Gapless Hartree-Fock Resummation Scheme for the O(N) Model

Yu. B. Ivanov·F. Riek·J. Knoll
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Abstract

A modified selfconsistent Hartree-Fock approximation to the lambda*phi^4 theory with spontaneously broken O(N) symmetry is proposed. It preserves all the desirable features, like conservation laws and thermodynamic consistency, of the selfconsistent Dyson scheme generated from a 2PI functional, also known as the Phi-derivable scheme, while simultaneously respecting the Nambu-Goldstone theorem in the chiral-symmetry broken phase. Various approximate resummation schemes are discussed.

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Yu. B. Ivanov, F. Riek, J. Knoll. 2005-05-11. Gapless Hartree-Fock Resummation Scheme for the O(N) Model. https://doi.org/10.1103/physrevd.71.105016

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