Anomaly-induced vacuum effective action with torsion: Covariant solution and ambiguities

The conformal anomaly in curved spacetime with antisymmetric torsion is reconsidered, taking into account new important details. We formulate, for the first time, the covariant solution of the anomaly -induced effective action. The covariant effective action includes local terms corresponding to total derivatives in the conformal anomaly. The contribution of massless fermions to these terms is characterized by multiplicative anomaly, coming from two different choices of doubling for the spinor operator. On the other hand, the nonlocal part of anomaly-induced action is free of ambiguities and admits a low-energy limit, similar to the effective potential in the metric-scalar theory.

Automated summary

This paper reexamines the conformal anomaly in curved spacetime with antisymmetric torsion, and presents a covariant solution of the anomaly-induced effective action. The solution includes both local terms corresponding to derivatives in the conformal anomaly, and a nonlocal part free of ambiguities with a low-energy limit similar to the effective potential in the metric-scalar theory.