Chair for Theoretical Physics III (Quantum Gravity)


Cosmology is the theory of the Universe and its evolution. As far as the geometric aspects are concerned it is a chapter in General Relativity focussing on solutions to Einstein’s field equations which are spatially homogeneous.  The best known solution and the one most relevant for our own Universe is the Friedmann-Robertson-Walker (FRW) solution which is not only homogeneous but also isotropic. It describes the Universe on very large scales beyond the extensions of galaxies and superclusters. Furthermore, it describes the Universe’ expansion. However, there are several puzzles that we face today in the cosmological setting. Very recent measurements, among others by the satellites WMAP and PLANCK, which focus on the Cosmological Microwave Background (CMB) show that the Universe is filled with only 5% baryonic matter, 25% dark matter and 70% of dark energy. The adjective “dark” just indicates that we do not know what it is.

The very same measurements (and others among which the measure of the matter distribution in the Universe) indicate that inhomogeneities and anisotropies need to be implemented in the cosmological standard model. In this setting, cosmologists introduce a so called inflaton field which represents the content of the Universe in very early times. The inflaton field decayed subsequently in matter components; and the further history of the Universe is an interplay between the gravitational force and the Standard Model forces. This suggests that also in Cosmolgy, quantum field theoretical aspects should be implemented. Backreactions of matter with gravitation might play an important role, especially for very early ages of the Universe.

Last updated on 2018-24-10 at 15:25