Optimized renormalization group flows

Optimized renormalization group flows

We study the optimization of exact renormalization group ~ERG! flows. We explain why the convergence of approximate solutions towards the physical theory is optimized by appropriate choices of the regularization. We consider specific optimized regulators for bosonic and fermionic fields and compare the optimized ERG flows with generic ones. This is done up to second order in the derivative expa...

Aspects of Renormalization Group Flows

ΛMS from renormalization group optimized perturbation

A variationally optimized perturbation, combined with renormalization group properties, can give approximations to certain nonperturbative quantities like the chiral symmetry breaking order parameters. We evaluate, up to third order in this modified perturbation, F π /Λ MS , where F π is the pion decay constant and Λ MS the basic QCD scale in the MS scheme. We obtain Λ

Spectral Functions in Holographic Renormalization Group Flows

The spectrum of two-point functions in a holographic renormalization group flow from an ultraviolet (UV) to an infrared (IR) conformal fixed point is necessarily continuous. For a toy model, the spectral function does not only show the expected UV and IR behaviours, but other interesting features such as sharp peaks and oscillations in the UV. The spectral functions for the SU(3)×U(1) flow in A...

Renormalization group flows for the second

Extending the results obtained in the case N odd, the effect of slightly relevant perturbations of the second parafermionic field theory with the symmetry ZN , for N even, are studied. The renormalization group equations, and their infra red fixed points exhibit the same structure in both cases. In addition to the standard flow from the p-th to the (p − 2)-th model, another fixed point correspo...