The origin of regular Newtonian potential in infinite derivative gravity

Abstract

It turns out that the infinite derivative gravity (IDG) is ghost-free and renormalizable when one chooses the exponential of an entire function. For this IDG case, the corresponding Newtonian potential generated from the delta function is non-singular at the origin. However, we will explicitly show that the source generating this non-singular potential is given not by the delta-function due to the point-like source of mass, but by the Gaussian mass distribution. This explains clearly why the IDG with the exponential of an entire function yields the finite potential at the origin.