Black holes, stars and exotic solutions of quadratic gravity
Quadratic curvature terms are commonly introduced in the action as first order corrections of General Relativity. In recent years solutions of such theories gained much attention and many static, spherically symmetric solutions have been found. However a classification of these solutions in terms of their gravitational properties is still lacking. In this talk we address this point in a generic quadratic action and present the phase diagram of the theory. Gravity in such theory is mediated by the standard massless graviton and two massive ones, one of which have negative energy states. The solutions are characterized by their ADM mass and the strengths of the Yukawa-like corrections associated with the massive gravitons. We show that the physical nature of the solutions is directly linked with their gravitational properties. In particular, in the case of compact stars, we have that different equations of state imply different Yukawa corrections to the gravitational potential.