Towards understanding the ultraviolet behavior of quantum loops in   infinite-derivative theories of gravity
  In this paper we will consider quantum aspects of a non-local, infinite-derivative scalar field theory - a $\it toy \, model$ depiction of a covariant infinite-derivative, non-local extension of Einstein's general relativity which has previously been shown to be free from ghosts around the Minkowski background. The graviton propagator in this theory gets an exponential suppression making it $\it asymptotically \, free$, thus providing strong prospects of resolving various classical and quantum divergences. In particular, we will find that at $1$-loop, the $2$-point function is still divergent, but once this amplitude is renormalized by adding appropriate counter terms, the ultraviolet (UV) behavior of all other $1$-loop diagrams as well as the $2$-loop, $2$-point function remains well under control. We will go on to discuss how one may be able to generalize our computations and arguments to arbitrary loops. 
Spyridon Talaganis, Tirthabir Biswas, Anupam Mazumdar
hep-th gr-qc hep-ph