Napredna pretraga

Pregled bibliografske jedinice broj: 994621

Causality and Renormalization in Finite-Time-Path Out-of-Equilibrium ϕ3 QFT

Dadić, Ivan; Klabučar, Dubravko
Causality and Renormalization in Finite-Time-Path Out-of-Equilibrium ϕ3 QFT // Particles, 2 (2019), 1; 92-102 doi:10.3390/particles2010008 (međunarodna recenzija, članak, znanstveni)

Causality and Renormalization in Finite-Time-Path Out-of-Equilibrium ϕ3 QFT

Dadić, Ivan ; Klabučar, Dubravko

Particles (2571-712X) 2 (2019), 1; 92-102

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Out-of-equilibrium quantum field theory ; dimensional renormalization ; finite-time-path formalism

Our aim is to contribute to quantum field theory (QFT) formalisms useful for descriptions of short time phenomena, dominant especially in heavy ion collisions. We formulate out-of-equilibrium QFT within the finite-time-path formalism (FTP) and renormalization theory (RT). The potential conflict of FTP and RT is investigated in gϕ3 QFT, by using the retarded/advanced ( R/A ) basis of Green functions and dimensional renormalization (DR). For example, vertices immediately after (in time) divergent self-energy loops do not conserve energy, as integrals diverge. We “repair” them, while keeping d<4 , to obtain energy conservation at those vertices. Already in the S-matrix theory, the renormalized, finite part of Feynman self-energy ΣF(p0) does not vanish when |p0|→∞ and cannot be split to retarded and advanced parts. In the Glaser–Epstein approach, the causality is repaired in the composite object GF(p0)ΣF(p0) . In the FTP approach, after repairing the vertices, the corresponding composite objects are GR(p0)ΣR(p0) and ΣA(p0)GA(p0) . In the limit d→4 , one obtains causal QFT. The tadpole contribution splits into diverging and finite parts. The diverging, constant component is eliminated by the renormalization condition ⟨0|ϕ|0⟩=0 of the S-matrix theory. The finite, oscillating energy-nonconserving tadpole contributions vanish in the limit t→∞ .

Izvorni jezik

Znanstvena područja


Projekt / tema
HRZZ-IP-2013-11-8799 - Tvar i međudjelovanja na ubrzivačima i u svemiru (Krešimir Kumerički, )

Institut "Ruđer Bošković", Zagreb,
Prirodoslovno-matematički fakultet, Zagreb