Functional renormalization group and 2PI effective action formalism

• Verfasst von: Blaizot, Jean-Paul [VerfasserIn]
• Verfasst von: Pawlowski, Jan M. [VerfasserIn]
• Verfasst von: Reinosa, Urko [VerfasserIn]
• Titel: Functional renormalization group and 2PI effective action formalism
• Verf.angabe: Jean-Paul Blaizot, Jan M. Pawlowski, Urko Reinosa
• E-Jahr: 2021
• Jahr: 8 June 2021
• Umfang: 60 S.
• Fussnoten: Available online 8 June 2021 ; Gesehen am 18.02.2022
• Titel Quelle: Enthalten in: Annals of physics
• Ort Quelle: Amsterdam [u.a.] : Elsevier, 1957
• Jahr Quelle: 2021
• Band/Heft Quelle: 431(2021), Artikel-ID 168549, Seite 1-60
• DOI: doi:10.1016/j.aop.2021.168549
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Functional Renormalization Group
• Sach-SW: Renormalization
• Sach-SW: Two-particle-irreducible formalism
• K10plus-PPN: 1790140617

Abstract

We combine two non-perturbative approaches, one based on the two-particle-irreducible (2PI) action, the other on the functional renormalization group (fRG), in an effort to develop new non-perturbative approximations for the field theoretical description of strongly coupled systems. In particular, we exploit the exact 2PI relations between the two-point and four-point functions in order to truncate the infinite hierarchy of equations of the functional renormalization group. The truncation is ”exact” in two ways. First, the solution of the resulting flow equation is independent of the choice of the regulator. Second, this solution coincides with that of the 2PI equations for the two-point and the four-point functions, for any selection of two-skeleton diagrams characterizing a so-called Φ-derivable approximation. The transformation of the equations of the 2PI formalism into flow equations offers new ways to solve these equations in practice, and provides new insight on certain aspects of their renormalization. It also opens the possibility to develop approximation schemes going beyond the strict Φ-derivable ones, as well as new truncation schemes for the fRG hierarchy.