1301.0632 (Astrid Eichhorn)

Faddeev-Popov ghosts in quantum gravity beyond perturbation theory    [PDF]

Astrid Eichhorn

Gauge-fixing in a non-perturbative regime can develop surprising features. In contrast to a perturbative scenario, where the ghost sector in most cases consists of a simple exponentiated Faddeev-Popov determinant, the Renormalization Group flow induces further operators in the ghost sector in the non-perturbative regime. Here, we concentrate on the case of asymptotically safe quantum gravity, which becomes non-perturbative in the ultraviolet. We point out that nonzero matter-ghost couplings and higher-order ghost self-interactions exist at a non-Gaussian fixed point for the gravitational couplings. Thus the ghost sector in this non-perturbative ultraviolet completion does not keep the structure of a simple Faddeev-Popov determinant. We discuss implications of the new ghost couplings for the Renormalization Group flow in gravity, and also for the Gribov problem.

View original: http://arxiv.org/abs/1301.0632