 Polyakov action

The Polyakov action introduces an independent worldsheet metric $g_{\alpha \beta }$:Its metric equation makes $g_{\alpha \beta }$ conformal to the induced worldsheet metric, reducing it classically to the Nambu–Goto action.

The Polyakov action is an important concept in theoretical physics, particularly in the context of string theory. It is a two-dimensional field theory that describes the dynamics of strings in spacetime. Named after the physicist Alexander Polyakov, the action provides a framework to model how strings propagate and interact in a background spacetime.