Physics Commons^™

There Is No Ambiguity In The Radiatively Induced Gravitational Chern-Simons Term, Brett Altschul

Faculty Publications

Quantum corrections to Lorentz- and C P T -violating QED in flat spacetime produce unusual radiative corrections, which can be finite but of undetermined magnitude. The corresponding radiative corrections in a gravitational theory are even stranger, since the term in the fermion action involving a preferred axial vector b μ would give rise to a gravitational Chern-Simons term that is proportional b μ , yet which actually does not break Lorentz invariance. Initially, the coefficient of this gravitational Chern-Simons term appears to have the same ambiguity as the coefficient for the analogous term in QED. However, this puzzle is resolved …