相关论文: Stringy signals from large-angle correlations in t…
Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of WMAP, including the alignment of large-scale multipoles. Models in which isotropy is spontaneously broken (e.g., by a scalar…
The cosmic microwave background (CMB) offers a unique window into the early universe, providing insights into cosmological parameters like the Hubble constant. Recent precise measurements of the CMB by experiments like Planck seem to point…
We cross-correlate the Saskatoon Ka and Q-Band Cosmic Microwave Background (CMB) data with different maps to quantify possible foreground contamination. We detect a marginal correlation (2 sigma) with the Diffuse Infrared Background…
We use analytic calculations of the post-recombination gravitational effects of cosmic strings to estimate the resulting CMB power spectrum, bispectrum and trispectrum. We place a particular emphasis on multipole regimes relevant for…
We present a significant update of the constraints on the Abelian Higgs cosmic string tension by cosmic microwave background (CMB) data, enabled both by the use of new high-resolution CMB data from suborbital experiments as well as the…
The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…
The network of cosmic strings generated in a phase transition during inflation enters the scaling regime later than that of usual strings. If it occurs after the recombination, temperature anisotropies of the cosmic microwave background…
I review recent progress towards a detailed understanding of the power spectrum of cosmic string perturbations induced on the Microwave Background (CMB). The use of a simple analytic model allows to include important effects that have not…
We investigate the potential of observations of anisotropies in the cosmic microwave background (CMB) and large-scale structure in the Universe to detect possible modifications of standard inflationary models by physics beyond the Planck…
In a recent paper, Gurzadyan & Penrose claim to have found directions in the sky around which there are multiple concentric sets of annuli with anomalously low variance in the cosmic microwave background (CMB). These features are presented…
We explore a model of the early universe in which the inflationary epoch is preceded by a cosmic bounce, and argue that this scenario provides a common origin to several of the anomalous features that have been observed at large angular…
The presence of a dipolar statistical anisotropy in the spectrum of cosmic microwave background (CMB) fluctuations was reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and has recently been confirmed in the Planck 2013 analysis…
We investigate the possibility that a heavy scalar field, whose mass exceeds the Hubble scale during inflation, could leave non-negligible signatures in the Cosmic Microwave Background (CMB) temperature anisotropy power spectrum through the…
We revisit a single field inflationary model based on Coleman-Weinberg potentials. We show that in small field Coleman-Weinberg inflation, the observed amplitude of perturbations needs an extremely small quartic coupling of the inflaton,…
In cosmological models where local cosmic strings are formed at the end of a period of inflation, the perturbations are seeded both by the defects and by the quantum fluctuations. In a subset of these models, for example those based on…
We apply new statistical tests on the four year 53 GHz DMR data and show that there is significant probability for the existence of coherent temperature discontinuities hidden in the CMB maps around the Galactic Poles. Comparing Monte Carlo…
The primordial anisotropies of the cosmic microwave background (CMB) are linearly polarized via Compton-scattering. The Faraday conversion process during the propagation of polarized CMB photons through regions of the large-scale structure…
A detailed search has been made for evidence of foreground contributions to the Cosmic Microwave Background (CMB) WMAP, such foregrounds being related to our Galaxy. We find remarkable results. On the largest angular scales we find…
While observations indicate that the predominant source of cosmic inhomogeneities are adiabatic perturbations, there are a variety of candidates to provide auxiliary trace effects, including inflation-generated primordial tensors and cosmic…
Fluctuations in the cosmic microwave background (CMB) temperature are being studied with ever increasing precision. Two competing types of theories might describe the origins of these fluctuations: ``inflation'' and ``defects''. Here we…