Cosmologies with a new coupling

by Dr Tomi Koivisto (Nordita)

Thursday 7 Feb 2013, 10:00 → 10:50 Europe/Stockholm

Nordita West Seminar Room

New high energy physics often predict scalar fields, but their existence is severely constrained by fifth force experiments. In the talk it is shown how a novel screening mechanism can emerge naturally in the presence of non-conformal couplings.

The field is then hidden from local experiments though it may have drastic effects at cosmological scales. It is argued that the so called disformal coupling arises very generically in extensions of General Relativity, and an explicit DBI-type string scenario that predicts the precise form of the coupling is presented.

This motivates the study of cosmological models with disformal interactions of quintessence fields and dark matter. The implications of such models to the cosmic microwave background and the large scale structure of the universe are discussed.