arXiv subjects

Burin Gumjudpai

Publications and source records attributed to Burin Gumjudpai.

39 records · Page 3Linked to original sources

arXiv2003

Brane-cosmology dynamics with induced gravity

The Friedmann equations for a brane with induced gravity are analyzed and compared with the standard general relativity and Randall-Sundrum cases. Randall-Sundrum gravity modified the early universe dynamics, whereas induced gravity changes the late universe evolution. The early and late time limits are investigated. Induced gravity effects can contribute to late-universe acceleration. This conditions for this are found. Qualitative analysis is given for a range of scalar field potentials.

gr-qc↗

arXiv2003

Introductory Overview of Modern Cosmology

A basic modern picture of the universe is given here. The lectures start from the historical ideas of a static universe. Then I move on to Newtonian cosmology and derive the main cosmological equations in the framework of Newtonian mechanics for the sake of simplicity. With a qualitative description of general relativity, the expansion of the universe and elementary idea of the hot Big Bang models are introduced. The problems of the hot Big Bang, inflation and structure formation are explained here in simple language.

astro-ph↗

arXiv2003

Density perturbations in a brane-world universe with dark radiation

We investigate the effects on cosmological density perturbations of dark radiation in a Randall-Sundrum 2 type brane-world. Dark radiation in the background is limited by observational constraints to be a small fraction of the radiation energy density, but it has an interesting qualitative effect in the radiation era. On large scales, it serves to slightly suppress the radiation density perturbations at late times, while boosting the perturbations in dark radiation. In a kinetic (stiff) era, the suppression is much stronger, and drives the density perturbations to zero.

gr-qc↗