Large-N quantum field theories are a playground for doing non-perturbative physics. Certain large-N theories turn out to be asymptotically free in d=4 and have features like bound states, just like quantum chromodynamics (QCD) and Yang–Mills theories. Their asymptotic freedom is connected to their apparent non-Hermiticity. However, when coupled with an antilinear symmetry, in many cases referred to as PT symmetry, […]