Non-local gravity in D-dimensions: Propagator, entropy and bouncing Cosmology

Understand

We present the graviton propagator for an infinite derivative, $D$-dimensional, non-local action, up to quadratic order in curvature around a Minkowski background, and discuss the conditions required for this class of gravity theory to be ghost-free.

• We then study the gravitational entropy for de-Sitter and Anti-de Sitter backgrounds, before comparing with a recently derived result for a Schwarzschild blackhole, generalised to arbitrary $D$-dimensions, whereby the entropy is given simply by the area law.
• A novel approach of decomposing the entropy into its $(r, t)$ and spherical components is adopted in order to illustrate the differences more clearly.
• We conclude with a discussion of de-Sitter entropy in the framework of a non-singular bouncing cosmology.