Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem

Bootstrapped Newtonian gravity was developed with the purpose of estimating the impact of quantum physics in the nonlinear regime of the gravitational interaction, akin to corpuscular models of black holes and inflation. In this work, we set the ground for extending the bootstrapped Newtonian picture to cosmological spaces. We further discuss how such models of quantum cosmology can lead to a natural solution to the cosmological constant problem.

Newtonian cosmology

This chapter discusses the construction of models of the universe, which is ambiguous in Newtonian theory. It presents some results recovered within the framework of general relativity, which in addition makes it possible to lay the foundation of the theory of the formation of large-scale structures in the universe such as galaxies and galactic clusters. The chapter first constructs models of an expanding sphere. If galaxies are treated as the particles of a uniform cloud which is spherically symmetric about the origin of an inertial frame, then these models describe a universe which expands and eventually collapses on itself. The chapter then turns to the pitfalls of the infinite Newtonian universe, the ‘Friedmann’ equation, the evolution of perturbations, and Olbers’s paradox.

Basics of FRW cosmology

An introduction to FRW cosmology. Comoving and physical coordinates and momenta. Background equation for single fluids and multi-components fluids. Radiation dominance, matter dominance, recombination and decoupling. Newtonian cosmology inside the horizon.