Conformality or confinement (II): One-flavor CFTs and mixed-representation QCD

TL;DR

This paper investigates four-dimensional QCD-like theories with one flavor and mixed representations, revealing phenomena like chiral symmetry breaking, confinement, and flow to conformal field theories, using duality and deformation techniques.

Contribution

It introduces new insights into chiral symmetry breaking and confinement mechanisms in one-flavor and mixed-representation theories, refining bounds on the conformal window.

Findings

Discrete chiral symmetry breaking via topological disorder operators

Confinement and mass gap generation from non-selfdual topological excitations

Flow to a conformal field theory in the R*4 limit

Abstract

We study QCD-like four dimensional theories in the theoretically controlled framework of deformation theory and/or twisted partition function on S*1 x R*3. By using duality, we show that a class of one-flavor theories exhibit new physical phenomena: discrete chiral symmetry breaking induced by the condensation of topological disorder operators, and confinement and the generation of mass gap due to new non-selfdual topological excitations. In the R*4 limit, we argue that the mass gap disappears, the chiral symmetry breaking vacua are of runaway type, and the theory flows to a CFT. We also study mixed-representation theories and find abelian chiral symmetry breaking by topological operators charged under abelian chiral symmetries. These are reminiscent to, but distinct, from Seiberg-Witten theory with matter, where 4d monopoles have non-abelian chiral charge. This examination also helps us refine our recent bounds on the conformal window. In an Addendum, we also discuss mixed vectorlike/chiral representation theories, obtain bounds on their conformal windows, and compare with the all-order beta function results of arXiv:0911.0931.