Related papers: Open universes from bubbles: an introduction and u…
Cosmic microwave background anisotropies provide a vast amount of cosmological information. Their full physical content and detailed structure can be understood in a simple and intuitive fashion through a systematic investigation of the…
We obtain the dipolar anisotropies in the arrival directions of ultra-high energy cosmic rays diffusing from nearby extragalactic sources. We discuss both the energy regime of spatial diffusion and the quasi-rectilinear one leading to just…
The evolution of moduli fields, which naturally appear in higher dimensional models such as brane worlds, and their effects on the anisotropies of the cosmological microwave background radiation is discussed.
A concise look at the big picture of particle physics, including the status of the Standard Model, neutrinos, supersymmetry, extra dimensions and cosmology. Based upon the theoretical summary presented at the XLIst Rencontres de Moriond on…
Observational cosmology is on the verge of new discoveries that will change the essence of our world-view. The matter concerns origin of initial conditions and physics of dark matter.
The early stages of the universe evolution are discussed according to the hot big bang model and the grand unified theories. The shortcomings of big bang are summarized and their resolution by inflationary cosmology is sketched.…
The past few years have seen several breakthroughs in particle astrophysics and cosmology. In several cases, new observations can only be explained with the introduction of new fundamental physics. In this talk I summarize some of these…
Our universe may have formed via bubble nucleation in an eternally-inflating background. Furthermore, the background may have a compact dimension---the modulus of which tunnels out of a metastable minimum during bubble nucleation---which…
Motivated by the back-reaction debate, and~some unexplained characteristics of the CMB, we investigate the possibility of some anisotropy in the universe observed around us. To this aim, we build up a novel prediction for the Hubble law for…
We discuss possible distortions of the ionization history of the Universe in the model with small scale baryonic clouds. The corresponding scales of the clouds are much smaller than the typical galactic mass scales. These clouds are…
This is a short overview of the ekpyrotic/cyclic model of the universe, an alternative to the standard big bang inflationary paradigm.
I review the current status of cosmology as emerging from recent observations of cosmic microwave background anisotropies as well as from other sources of cosmological information.
The Cosmic Microwave Background (CMB) power spectrum derived from the first year WMAP data demonstrates an intriguing lack of power at large scales that cannot be accounted for within the framework of the standard cosmological model. We…
The nucleation and evolution of bubbles are investigated in the model of an $O(3)$-symmetric scalar field coupled to gravity in the high temperature limit. It is shown that, in addition to the well-known bubble of which the inside region is…
A particular class of flat Emergent Universe scenario is studied in light of recent observational data. Observationally permissible ranges of values are obtained for the model parameters. The class of model studied here can accommodate…
The aim of this thesis is to question some of the basic assumptions that go into building the $\Lambda$CDM model of our universe. The assumptions we focus on are the initial conditions of the universe, the fundamental forces in the universe…
The observed structures in the universe are thought to have arisen from gravitational instability acting on small fluctuations generated in the early universe. These spatial fluctuations are imprinted on the CMBR as angular anisotropies.…
We explore the dynamics and evolution of the Universe at early and late times, focusing on both dark energy and extended gravity models and their astrophysical and cosmological consequences. Modified theories of gravity not only provide an…
I briefly review the main ideas and challenges involved in the computation of the observed baryonic asymmetry of the Universe.
In this follow-up to our paper from 2005, we briefly discuss the implications of the apparent detection of B modes in the Cosmic Microwave Background for the issues raised in that paper. We argue that under the assumptions of eternal…