Nonlocal Newtonian Cosmology

TL;DR

This paper investigates how nonlocal gravity, a modification of Einstein's theory, can potentially explain cosmic structure formation without dark matter by extending its Newtonian cosmological implications.

Contribution

It extends nonlocal gravity to the cosmological domain and formulates a nonlocal Zel'dovich model to explore structure formation without dark matter.

Findings

Nonlocal gravity can mimic dark matter effects in cosmology.

The nonlocal Zel'dovich model provides new insights into structure formation.

Potential to explain cosmic structures without dark matter.

Abstract

We explore some of the cosmological implications of the recent classical nonlocal generalization of Einstein's theory of gravitation in which nonlocality is due to the gravitational memory of past events. In the Newtonian regime of this theory, the nonlocal character of gravity simulates dark matter in spiral galaxies and clusters of galaxies. However, dark matter is considered indispensable as well for structure formation in standard models of cosmology. Can nonlocal gravity solve the problem of structure formation without recourse to dark matter? Here we make a beginning in this direction by extending nonlocal gravity in the Newtonian regime to the cosmological domain. The nonlocal analog of the Zel'dovich solution is formulated and the consequences of the resulting nonlocal Zel'dovich model are investigated in detail.