Université de GenèveDépartement de Physique ThéoriqueCAP Genève

Cosmic microwave background

The Cosmic Microwave Background (CMB) is due to the thermal photons remaining from the hot initial state of the Universe (commonly referred to as Big Bang). They have been emitted when the Universe became sufficiently cool so that neutral hydrogen could form. At this time, when the Universe was only about 380'000 years old (very little compared to its current age of 13.8 billion years in the standard model) the cosmic plasma became transparent to photons. The CMB is effectively a 'photograph' of the young Universe, showing the tiny fluctuations that are the seeds of the large-scale structure observed today. It is the most precious cosmological dataset for two reasons: Firstly, its anisotropies and soon also its polarization are measured with high precision, by the WMAP and Planck satellites. Secondly, we understand them well theoretically and can calculate them to good precision with cosmological perturbation theory. The combination of these two reasons means that we can use the CMB to estimate the parameters of the cosmological standard model and its variants, e.g. including primordial magnetic fields, to excellent precision (in cosmology this means a couple percent). According to the current understanding, the anisotropies and polarization of the CMB contain information about the earliest epoch of the Universe, inflation. Especially Non-Gaussianities in the distribution of these quantities can contain information about particle physics interactions at 1016 GeV, an energy about 12 orders of magnitude larger than what can be achieved the most powerful present particle physics accelerator, the LHC. A pedagogical introduction to the physics of the CMB is given on Wayne Hu's website.

Recent publications and presentations on this topic
Date: 15. November 2013
Members involved: Ruth Durrer, Daniel Figueroa, Martin Kunz
Topics: Cosmic microwave background, Topological defects
Type: Publication
Date: 5. July 2013
Members involved: Enea Di Dio, Francesco Montanari, Ruth Durrer
Topics: Large-scale structure, General relativity, Cosmic microwave background
Type: Publication
Date: 29. November 2012
Members involved: Azadeh Moradinezhad Dizgah
Topics: Cosmic Reionization, Cosmic microwave background
Type: Publication
Date: 6. March 2012
Members involved: Antonio Riotto
Topics: Inflation, Cosmic microwave background, Non-Gaussianity
Type: Publication
Date: 25. January 2012
Members involved: Ruth Durrer
Topics: Cosmic microwave background, Dark energy, Dark matter, Large-scale structure, Inflation
Type: Presentation
Date: 25. January 2012
Members involved: Mona Frommert
Topics: Cosmic microwave background
Type: Presentation
Date: 3. January 2012
Members involved: Mona Frommert, Ruth Durrer
Topics: Cosmic microwave background, Non-Gaussianity
Type: Publication
Date: 1. July 2011
Members involved: Martin Kunz, Mona Frommert
Topics: Cosmic microwave background, Large-scale structure, Non-Gaussianity
Type: Publication
Date: 14. March 2011
Members involved: Mona Frommert
Topics: Cosmic microwave background
Type: Presentation
Date: 25. February 2011
Members involved: Ruth Durrer, Elisa Fenu, Marc Vonlanthen
Topics: Magnetic fields, Cosmic microwave background
Type: Publication

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Département de Physique Théorique
Université de Genève
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