Cosmography: Cosmology without the Einstein equations

The Averaging Problem in Cosmology and Macroscopic Gravity

The averaging problem in cosmology and the approach of macroscopic gravity to resolve the problem is discussed. The averaged Einstein equations of macroscopic gravity are modified on cosmological scales by the macroscopic gravitational correlation tensor terms as compared with the Einstein equations of general relativity. This correlation tensor satisfies a system of structure and field equatio...

Cosmography, Decelerating Past, and Cosmological Models: Learning the Bayesian Way

In this paper, using a significantly improved version of the model-independent, cosmographic approach to cosmology (John, M. V. 2004, ApJ, 614, 1), we address an important question: Was there a decelerating past for the universe? To answer this, the Bayes’s probability theory is employed, which is the most appropriate tool for quantifying our knowledge when it changes through the acquisition of...

Brane-world Cosmology

Brane-world models, where observers are restricted to a brane in a higher dimensional spacetime, offer a novel perspective on cosmology. I discuss some approaches to cosmology in extra dimensions and some interesting aspects of gravity and cosmology in brane-world models. COSMOLOGY AFTER EINSTEIN A century after Einstein first proposed his theory of relativity, it has become a cornerstone of th...

Physics 171. General Relativity. Professor Dine Fall, 2008. Handout: A Primer on Curvature, the Einstein Equations and Cosmology (and Homework Set 7)

Quantizing Cosmology: A Simple Approacha

I discuss the problem of inflation in the context of Friedmann-Robertson-Walker Cosmology and show how, after a simple change of variables, to quantize the problem in a way which parallels the classical discussion. The result is that two of the Einstein equations arise as exact equations of motion and one of the usual Einstein equations (suitably quantized) survives as a constraint equation to ...