Minicourse on Universality in the Epsilon-Expansion

One novelty of the approach is the ability to construct epsilon-series for the OPE coefficients and not only for the critical exponents (i.e. CFT scaling dimensions). 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 CFTs in d = 2, while for odd m the theories are non-unitary CFTs and start at m = 3 with the Lee-Yang universality class. An important outcome of this functional 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.

 

The second part of the course will show how the FPRG formalism allows a straightforward generalization to the multicomponent scalar field case (arbitrary N) with almost no need for additional computations. We will explore many examples of known theories – including O(N), Potts and Cubic models – together with more recent topics like Platonic Field Theories and multicritical O(N) models.

 

Finally we present the recent full classification of dc=4 and N = 2,3,4, dc=6 and N=2,3 and dc=10/3 and N=2 multicomponent universality classes and conclude with an overview of current research topics in the field.

 

There is no registration fee.

July 12-20, 2022

ICTP-SAIFR, São Paulo, Brazil

Auditorium of IFT-UNESP

Announcement:

Lecturer:

Alessandro Codello (UdelaR – Montevideo, Uruguay)

Organizers:

Alberto Tonero (Carleton University, Canada)