Solutions to the reconstruction problem in asymptotic safety

Jul 30, 2015
32 pages
Published in:
  • JHEP 11 (2015) 094
  • Published: Nov 13, 2015
e-Print:

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Abstract: (Springer)
Starting from a full renormalised trajectory for the effective average action (a.k.a. infrared cutoff Legendre effective action) Γk_{k} , we explicitly reconstruct corresponding bare actions, formulated in one of two ways. The first step is to construct the corresponding Wilsonian effective action Sk^{k} through a tree-level expansion in terms of the vertices provided by Γk_{k} . It forms a perfect bare action giving the same renormalised trajectory. A bare action with some ultraviolet cutoff scale Λ and infrared cutoff k necessarily produces an effective average action ΓkΛ_{k}^{Λ} that depends on both cutoffs, but if the already computed SΛ^{Λ} is used, we show how ΓkΛ_{k}^{Λ} can also be computed from Γk_{k} by a tree-level expansion, and that ΓkΛ_{k}^{Λ}  → Γk_{k} as Λ → ∞. Along the way we show that Legendre effective actions with different UV cutoff profiles, but which correspond to the same Wilsonian effective action, are related through tree-level expansions. All these expansions follow from Legendre transform relationships that can be derived from the original one between ΓkΛ_{k}^{Λ} and Sk^{k} .
Note:
  • 32 pages
  • Renormalization Group
  • Models of Quantum Gravity
  • effective action
  • tree approximation
  • trajectory
  • infrared
  • asymptotic safety
  • ultraviolet
  • partition function
  • duality