26–28 Sept 2018
Mainz Institute for Theoretical Physics, Johannes Gutenberg University
Europe/Berlin timezone

Universality in the epsilon-expansion

26 Sept 2018, 15:00
45m
02.430 (Mainz Institute for Theoretical Physics, Johannes Gutenberg University)

02.430

Mainz Institute for Theoretical Physics, Johannes Gutenberg University

Staudingerweg 9 / 2nd floor, 55128 Mainz

Speaker

Dr Alessandro Codello

Description

After reviewing the Functional reformulation of the standard Perturbative RG (FPRG), I'll describe the classification of universality classes in arbitrary dimension within the epsilon-expansion and the relative determination of CFT data. In the single component case, universality classes are represented by renormalizable scalar QFTs with self-interacting potentials of highest monomial φ^m below their upper critical dimensions dc = 2m/(m -2). For even integers, m ≥ 4 these theories coincide with the Landau-Ginzburg description of multi-critical phenomena and interpolate with the unitary minimal models in d = 2, while for odd m the theories are non-unitary and start at m = 3 with the Lee-Yang universality class. An important outcome of this analysis is the realization of the existence of a new non-trivial family of d = 3 universality classes with upper critical dimension dc = 10/3. Subsequently, I will show how the FPRG formalism allows a straightforward generalization to the multicomponent case, with almost no need for additional computations. The classification of multicomponent universality classes if far from complete and I will discuss the present state of knowledge with few examples, including Potts and O(N) models. I will conclude with a review and outlook of the application of the epsilon-expansion to Quantum Gravity.

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