Recent studies of the ultraviolet behavior of pure gravity suggest that it admits a non-Gaussian attractive fixed point, and therefore that the theory is asymptotically safe. We consider the effect on this fixed point of massless minimally coupled matter fields. The existence of a UV attractive fixed point puts bounds on the type and number of such fields.

• Received 23 December 2002

DOI:https://doi.org/10.1103/PhysRevD.67.081503