In this article we review the theory of cosmological inflation with a particular focus on the beautiful connection it provides between the physics of the very small and observations of the very large. We explain how quantum mechanical fluctuations during the inflationary era become macroscopic density fluctuations which leave distinct imprints in the cosmic microwave background (CMB). We descri...

We show that entropy perturbations can eliminate instabilities and oscillations, in the mass power spectrum of the quartessence Chaplygin models. Our results enlarge the current parameter space of models compatible with large scale structure and cosmic microwave background (CMB) observations.

We discuss the nature of the possible high-l excess in the Cosmic Microwave Background (CMB) anisotropy power spectrum observed by the Cosmic Background Imager (CBI). We probe the angular structure of the excess in the CBI deep fields and investigate whether it could be due to the scattering of CMB photons by hot electrons within clusters, the Sunyaev-Zeldovich (SZ) effect. We estimate the dens...

The cosmological magnetic field is one of the important physical quantities which affect strongly the cosmic microwave background (CMB) power spectrum. Recent CMB observations have been extended to higher multipoles l &1000, and they resultantly exhibit an excess power than the standard model prediction in cosmological theory which best fits the Wilkinson Microwave Anisotropy Probe (WMAP) data ...

The presence of a primordial magnetic field would have induced resonant conversions between photons and axion-like particles (ALPs) during the thermal history of the Universe. These conversions would have distorted the blackbody spectrum of the cosmic microwave background (CMB). In this context, we derive bounds on the photon-ALP resonant conversions using the high precision CMB spectral data c...

With polarization of the cosmic microwave background (CMB) now detected, and confirmed by several independent experiments, the next goal is to characterise accurately its statistical properties. In these lecture notes we review the physical motivation for pursuing CMB polarization, and the basic statistical properties of the polarization fields. We then discuss some of the key aspects of the an...

If X-rays observed from any extragalactic radio jets are due to inverse Compton scattering on the cosmic microwave background (CMB) radiation, then such a source will be detectable with the same surface brightness anywhere in the more distant universe. Chandra observations imply that such systems do exist, and will therefore serve as Cosmic Beacons out to the redshift at which they form.

Following Loeb (2001), we explore the imprint of the resonant 6708Å line opacity of neutral lithium on the temperature and polarization anisotropies of the cosmic microwave background (CMB) at observed wavelengths of 250–350μm (0.9–1.2 THz). We show that if lithium recombines in the redshift range of z = 400–500 as expected, then the standard CMB anisotropies would be significantly modified in ...

We present a brief review of current theory and observations of the cosmic microwave background (CMB). New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique bas...

In this talk presented at the 5th Rencontres du Vietnam 2004, we discuss our preliminary investigations into voids of primordial origin. We show that if voids in the cold dark matter distribution existed at the epoch of decoupling, they could contribute significantly to the apparent rise in cosmic microwave background (CMB) power on small scales detected by the Cosmic Background Imager (CBI) De...