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001-es BibID:	BIBFORM125532
035-os BibID:	(Scopus)85198932373 (WOS)001266674300001
Első szerző:	Hariharakrishnan, S.
Cím:	Perturbative versus non-perturbative renormalization / Hariharakrishnan, S; Jentschura, U D; Márián, I G; Szabó, K; Nándori, I
Dátum:	2024
ISSN:	0954-3899
Megjegyzések:	Approximated functional renormalization group (FRG) equations lead to regulator-dependent ?-functions, in analogy to the scheme-dependence of the perturbative renormalization group (pRG) approach. A scheme transformation redefines the couplings to relate the ?-functions of the FRG method with an arbitrary regulator function to the pRG ones obtained in a given scheme. Here, we consider a periodic sine-Gordon scalar field theory in d = 2 dimensions and show that the relation of the FRG and pRG approaches is intricate. Although both the FRG and the pRG methods are known to be sufficient to obtain the critical frequency ? c 2 = 8 ? of the model independently of the choice of the regulator and the renormalization scheme, we show that one has to go beyond the standard pRG method (e.g. using an auxiliary mass term) or the Coulomb-gas representation in order to obtain the ?-function of the wave function renormalization. This aspect makes the scheme transformation non-trivial. Comparing flow equations of the two-dimensional sine-Gordon theory without any scheme-transformation, i.e. redefinition of couplings, we find that the auxiliary mass pRG ?-functions of the minimal subtraction scheme can be recovered within the FRG approach with the choice of the power-law regulator with b = 2, which therefore constitutes a preferred choice for the comparison of FRG and pRG flows. ? 2024 The Author(s). Published by IOP Publishing Ltd.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk functional renormalization group perturbative renormalization group renormalization scheme-transformation sine-Gordon model
Megjelenés:	Journal Of Physics G-Nuclear And Particle Physics. - 51 : 8 (2024), p. , p. 1-22. -
További szerzők:	Jentschura, Ulrich David (fizikus) Márián István Gábor (1992-) (fizikus) Szabó K. Nándori István (1973-) (fizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM088493
Első szerző:	Márián István Gábor (fizikus)
Cím:	The numerically optimized regulator and the functional renormalization group / I. G. Márián, U. D. Jentschura, I. Nándori
Dátum:	2014
ISSN:	0954-3899
Megjegyzések:	We aim to optimize the functional form of the compactly supported smooth (CSS) regulator within the functional renormalization group (RG), in the framework of bosonized two-dimensional quantum electrodynamics (QED 2 ) and of the three-dimensional O(N = 1) scalar field theory in the local potential approximation (LPA). The principle of minimal sensitivity (PMS) is used for the optimization of the CSS regulator, recovering all the major types of regulators in appropriate limits. Within the investigated class of functional forms, a thorough investigation of the CSS regulator, optimized with two different normalizations within the PMS method, confirms that the functional form of a regulator first proposed by Litim is optimal within the LPA. However, Litim's exact form leads to a kink in the regulator function. A form of the CSS regulator, numerically close to Litim's limit while maintaining infinite differentiability, remains compatible with the gradient expansion to all orders. A smooth analytic behavior of the regulator is ensured by a small, but finite value of the exponential fall-off parameter in the CSS regulator. Consequently, a compactly supported regulator, in a parameter regime close to Litim's optimized form, but regularized with an exponential factor, appears to have favorable properties and could be used to address the scheme dependence of the functional RG, at least within the approximations employed in the studies reported here.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Journal Of Physics G-Nuclear And Particle Physics. - 41 : 5 (2014), p. 1-17. -
További szerzők:	Jentschura, Ulrich David (fizikus) Nándori István (1973-) (fizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: