3 dimensional QED at low energies from the $\epsilon$ expansion

by Emmanuel Stamou (Chicago)

Tuesday 26 Jun 2018, 15:00 → 16:00 Europe/Berlin

SR 2 (Building 2A)

In 3 dimensions, QED is a free theory at high energies. However, like QCD in 4 dimensions, QED3 becomes strongly coupled when evolved to low energies. If the number of fermions/flavours ($N_f$) is large, the strongly coupled theory is conformal, but this can change for small values of Nf. Understanding the range of conformality in QED3 and related theories, i.e., QCD3, is an active field of research connecting various fiels, e.g., lattice, large-N approaches, bootstrapping. In this talk, I discuss a mechanism that may dynamically force the theory out of conformality; a strong RG flow can render four-fermion operators relevant and destabilize the conformal fixed point. I discuss how to quantify this via the method of $\epsilon$ expansion at one- and two-loop. I will also discuss the scheme and evancescent (in)dependence of this approach and generalise some result to the case of 3 dimensional QCD.