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arXiv · hep-th/0006153

Functional Differential Equations for the Free Energy and the Effective Energy in the Broken-Symmetry Phase of phi^4-Theory and Their Recursive Graphical Solution

A. Pelster·H. Kleinert
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Abstract

Extending recent work on QED and the symmetric phase of the euclidean multicomponent scalar ϕ^4-theory, we construct the vacuum diagrams of the free energy and the effective energy in the ordered phase of ϕ^4-theory. By regarding them as functionals of the free correlation function and the interaction vertices, we graphically solve nonlinear functional differential equations, obtaining loop by loop all connected and one-particle irreducible vacuum diagrams with their proper weights.

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A. Pelster, H. Kleinert. 2000-06-20. Functional Differential Equations for the Free Energy and the Effective Energy in the Broken-Symmetry Phase of phi^4-Theory and Their Recursive Graphical Solution. https://doi.org/10.1016/s0378-4371(02)01932-5

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