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

A cura di Prof. Ilya Shapiro (Università Juiz de Fora (Brasile))

lunedì 20 giu 2022, 14:00 → 15:00 Europe/Rome

AULA GRASSANO

Torsion gravity, or Einstein-Cartan theory, is the simplest 

way to go beyond the framework of general relativity. The 

main advantage of torsion is the possibility of linking the spin 

of fermionic matter to spacetime geometry. Semiclassical 

gravity with torsion has been consistently formulated in 

80-is, including the renormalizable theory and derivation 

of conformal anomaly. After a brief review of the subject, 

I will report on the new results concerning the covariant 

nonlocal form of the anomaly-induced effective action. This 

action manifests a qualitatively new kind of ambiguity coming 

from the multiplicative anomaly in the fermionic contribution. 

This ambiguity concerns total derivative terms in the 

anomaly or, equivalently, the local nonconformal terms in 

the effective action. On the other hand, the nonlocal part 

of anomaly-induced effective action is free of ambiguity 

and admits a low-energy limit in a form similar to the 

effective potential in the scalar theory.