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arXiv · 1302.1311

Asymptotic behavior and critical coupling in the scalar Yukawa model from Schwinger-Dyson equations

Vladimir E. Rochev
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Abstract

A sequence of $n$-particle approximations for the system of Schwinger-Dyson equations is investigated in the model of a complex scalar field $\phi$ and a real scalar field $\chi$ with the interaction $g\phi^*\phi\chi$. In the first non-trivial two-particle approximation, the system is reduced to a system of two nonlinear integral equations for propagators. The study of this system shows that for equal masses a critical coupling constant $g^2_c$ exists, which separates the weak- and strong-coupling regions with the different asymptotic behavior for deep Euclidean momenta. In the weak-coupling region ($g^2 g^2_c$), the propagators are asymptotically constant, which corresponds to the ultra-local limit. For unequal masses, the critical point transforms into a segment of values, in which there are no solutions with a self-consistent ultraviolet behavior without Landau singularities.

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Vladimir E. Rochev. 2013-02-06. Asymptotic behavior and critical coupling in the scalar Yukawa model from Schwinger-Dyson equations. https://doi.org/10.1088/1751-8113/46/18/185401

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