Confinement and XSB in QCD: Mysteries and beauty of soliton dynamics in nonAbelian gauge theories

Abstract

Deep insights into the possible infrared dynamics of strongly-coupled nonAbelian gauge theories such as QCD come from the analyses of ${\cal N}=1$ or ${\cal N}=2$ supersymmetric gauge theories. Central in the whole discussion will be the topological soliton monopoles and vortices and their quantum dynamics. We review the arguments that nonAbelian monopoles, free from the classic "difficulties", can be defined semi-classically via the topology and stability connection to the better understood nonAbelian vortices. Recent results on $CP^{N-1}$ models on $2D$ worldsheet of finite width, establish the quantum mechanical nature of such nonAbelian monopoles. An interesting class of RG flows and emergence of confining vacua "nearby" strongly-coupled infrared-fixed point (IRFP) conformal theories are discussed in the context of most singular vacua in ${\cal N}=2$ supersymmetric QCD. Certain analogy with the real-world QCD is drawn. In many systems, color-flavor locking emerges as a crucial mechanism for the gauge system to avoid dynamical Abelianization.