Unifying renormalization group and the continuous wavelet transform

TL;DR

This paper demonstrates that the renormalization group can be viewed as a symmetry group within a framework based on scale-dependent functions, connecting it with the continuous wavelet transform and providing a finite, physically relevant approach.

Contribution

It unifies the renormalization group with the continuous wavelet transform, introducing a finite, scale-dependent function space that aligns with physical measurement principles.

Findings

Reproduces standard RG results for the $$ model.

Shows the RG as a symmetry group in a scale-dependent function space.

Connects the wavelet transform with the effective action in quantum field theory.

Abstract

It is shown that the renormalization group turns to be a symmetry group in a theory initially formulated in a space of scale-dependent functions, i.e, those depending on both the position $x$ and the resolution $a$. Such theory, earlier described in {\em Phys.Rev.D} 81(2010)125003, 88(2013)025015, is finite by construction. The space of scale-dependent functions $\{ \phi_a(x) \}$ is more relevant to physical reality than the space of square-integrable functions $\mathrm{L}^2(R^d)$, because, due to the Heisenberg uncertainty principle, what is really measured in any experiment is always defined in a region rather than point. The effective action $\Gamma_{(A)}$ of our theory turns to be complementary to the exact renormalization group effective action. The role of the regulator is played by the basic wavelet -- an "aperture function" of a measuring device used to produce the snapshot of a field $\phi$ at the point $x$ with the resolution $a$. The standard RG results for $\phi^4$ model are reproduced.