Graviballs and Dark Matter

We investigate the possible existence of graviballs, a system of bound gravitons, and show that two gravitons can be bound together by their gravitational interaction. This idea connects to the gravitational geon studied by Brill and Hartle. However the calculations performed here rely on the formalism and techniques of quantum field theory, specifically on low-energy quantum gravity. We argue that the graviball is a viable dark matter candidate and we compute the associated gravitational lensing.