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A<sc>bstract</sc> We study line defects in the fermionic CFTs in the Gross-Neveu-Yukawa universality class in dimensions 2< d <4. These CFTs may be described as the IR fixed points of the Gross-Neveu-Yukawa (GNY) model ind= 4 −ϵ, or as the UV fixed points of the Gross-Neveu (GN) model, which can be studied using the largeNexpansion in 2< d <4. These models admit natural line defects obtained by integrating over a line either the scalar field in the GNY description, or the fermion bilinear operator in the GN description. We compute the beta function for the defect RG flow using both the epsilon expansion and the largeNapproach, and find IR stable fixed points for the defect coupling, thus providing evidence for a non-trivial IR DCFT. We also compute some of the DCFT observables at the fixed point, and check that theg-function associated with the circular defect is consistent with theg-theorem for the defect RG flow.
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Vacuum energy and renormalization of the field-independent term
Abstract Due to its construction, the nonperturbative renormalizationgroup (RG) evolution of the constant, field-independent term (which is constantwith respect to field variations but depends on the RG scale k ) requiresspecial care within the Functional Renormalization Group (FRG) approach.In several instances, the constant term of the potential has nophysical meaning. However, there are special cases where it receives importantapplications. In low dimensions ( d = 1), in a quantum mechanical model, thisterm is associated with the ground-state energy of the anharmonic oscillator.In higher dimensions ( d = 4), it is identical to the Λ termof the Einstein equationsand it plays a role in cosmic inflation. Thus, instatistical field theory, in flat space, the constant term could be associatedwith the free energy, while in curved space, it could be naturally associatedwith the cosmological constant. It is known that one has to use a subtractionmethod for the quantum anharmonic oscillator in d = 1 to remove the k 2 term that appears in the RGflow in its high-energy (UV) limit in order to recover thecorrect results for the ground-state energy. The subtraction is needed becausethe Gaussian fixed point is missing in the RG flow once the constant term isincluded. However, if the Gaussian fixed point is there, no furthersubtraction is required. Here, we propose a subtraction method for k 4 and k 2 terms of the UV scaling of the RG equations for d = 4 dimensions if theGaussian fixed point is missing in the RG flow with the constant term. Finally,comments on the application of our results to cosmological models are provided.
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- Award ID(s):
- 2110294
- PAR ID:
- 10330481
- Date Published:
- Journal Name:
- Journal of Cosmology and Astroparticle Physics
- Volume:
- 2022
- Issue:
- 03
- ISSN:
- 1475-7516
- Page Range / eLocation ID:
- 062
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/1475-7516/2022/03/062
