Gross-Neveu and Thirring models. Covariant Gaussian analysis

Journal Article · Sat Jul 15 00:00:00 EDT 1989 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.40.523· OSTI ID:5938501

Rosenstein, B; Kovner, A

Two-dimensional fermionic theories, the SU(/ital N/) Gross-Neveu and themassive Thirring models, are analyzed in the covariant Gaussian approximation.In the Gross-Neveu model we find three phases (renormalizations). In one ofthem the results coincide with the leading order in 1//ital N/ expansion. Inthe other two phases the gap equation has no solution and there are nofermionic excitations in the spectrum of the theory. It is argued that thoserenormalizations are relevant for /ital N/=1,2. The massive Thirringmodel is found to possess a line of ultraviolet fixed points. In the limit/ital m//sub /ital b///r arrow/0 the axial symmetry is not broken. The 2/r arrow/2/ital S/-matrix element for the nonasymptotically free phase is calculated andit qualitatively agrees with the exact expression. We also find anasymptotically free phase with vanishing bare coupling.

• Research Organization: Theory Group, Department of Physics, University of Texas, Austin, Texas 78712(IL); School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
• OSTI ID: 5938501
• Journal Information: Phys. Rev. D; (United States), Vol. 40:2
• Country of Publication: United States
• Language: English

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