A flow equation for f(R) gravity and some of its exact solutions

Understand

We write a Renormalization Group (RG) equation for the function f in a theory of gravity in the f(R) truncation.

• Our equation differs from previous ones due to the exponential parametrization of the quantum fluctuations and to the choice of gauge.
• The cutoff procedure depends on three free parameters, and we find that there exist discrete special choices of parameters for which the flow equation has fixed points where f=f_0+f_1 R+f_2 R^2.
• For other values of the parameters the solution seems to be continuously deformed.