Reconstructing the Distortion Function for Nonlocal Cosmology

Understand

We consider the cosmology of modified gravity models in which Newton's constant is distorted by a function of the inverse d'Alembertian acting on the Ricci scalar.

• We derive a technique for choosing the distortion function so as to fit an arbitrary expansion history.
• This technique is applied numerically to the case of LambdaCDM cosmology, and the result agrees well with a simple hyperbolic tangent.