Let us look at the Polyakov action for a string moving in a spacetime with metric $g_{\mu \nu}(X)$:$$S_P = -{1\over{4\pi \alpha'}} \int d^2 \sigma \sqrt{-\gamma} \gamma^{ab} \partial_a X^\mu \partial_b X^\nu g_{\mu\nu}(X) \tag{1}$$ and suppose there exists a Killing vector $k_\mu$ in spacetime satisfying Killing's equation
$$\nabla_\mu k_\nu + \nabla_\nu k_\mu = 0.\tag{2}$$
Does this lead to a symmetry of the Polyakov action?

This post imported from StackExchange Physics at 2016-01-17 15:57 (UTC), posted by SE-user Ham