Wess-Zumino-Witten models and an example from holography

Wess-Zumino-Witten (WZW) models are a class of 2D CFTs which describe the propagation of strings on a group manifold. They are among the rare examples of exactly solvable field theories and so they give insight into non-perturbative physics. We will see how this solvability is manifest classically as formal integrability and at the quantum level due to the existence of an infinite-dimensional current algebra that constrains the dynamics. We'll finish with an example from holography: $\Lambda < 0$ gravity in 2+1 dimensions has a holographic dual described by an $SL(2,\mathbb{R})$ WZW model.