conformal anomaly

In quantum field theory a conformal anomaly is a quantum anomaly that breaks conformal invariance. Discussion of the conformal anomaly (Weyl anomaly) of the relativistic string as an anomalous action functional is in (Freed 86, 2.). The following summary of this is taken from this MO answer by Pavel Safronov. Let be a compact surface (worldsheet) and a Riemannian manifold (spacetime). The string partition function looks like Here is the space of Riemannian metrics on and is the standard -model..