Wilsonian renormalization group and thermal field theory in the Schwinger-Keldysh closed-time-path formalism

Frangi, Giorgio (author), Grozdanov, Sašo (author)

We study perturbative Wilsonian renormalization group (RG) for the scalar $\phi^4$ theory at finite temperature to one loop order in the Schwinger-Keldysh closed-time-path (CTP) formalism. By explicitly integrating out the UV modes, we show how effective interactions coupling the two branches of the CTP contour arise. This provides a microscopic derivation of the type of effective CTP actions used in the literature. While the full effective theory has no critical points, we instead proceed to study critical properties of the RG flow in a reduced space of complex couplings that characterize certain time-ordered correlators and show the existence of two novel fixed points in d=4 spacetime dimensions. We relate one to the Wilson-Fisher fixed point known to exist only in 4-$\epsilon$ dimensions, and the other to the standard Gaussian fixed point.

• Language: English
• Keywords: renormalization group, effective field theory, finite temperature field theory, critical phenomena
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 085034-1-085034-17
• Numbering: Vol. 111, iss. 8
• PID: 20.500.12556/RUL-168887
• UDC: 539.1
• ISSN on article: 2470-0010
• DOI: 10.1103/PhysRevD.111.085034
• COBISS.SI-ID: 234837251
• Publication date in RUL: 06.05.2025

Record is a part of a journal

• Title: Physical review
• Shortened title: Phys. rev., D
• Publisher: American Physical Society
• ISSN: 2470-0010
• COBISS.SI-ID: 29757223

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: renormalizacijska grupa, teorija polja, efektivna teorija polja, kritični pojavi