Non-Gaussian signatures of multi-field inflation from string theory

• Applicant: Professor Dr. Jens Niemeyer
• Subject Area: Astrophysics and Astronomy
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 210170592

Multi-field inflationary models are natural in string theory, yet their predictions are degenerate. If non-Gaussianities are observed in fluctuations of the cosmic microwave background radiation (CMBR) by the Planck satellite, simple single-field models are ruled out. Lifting this degeneracy is thus a most pressing task. Multi-field scenarios often include additional effects during inflation, such as the decay of fields or particle production and the associated backreaction. These effects can lead to unique, non-Gaussian signatures in higher order correlation functions of fluctuations in the CMBR. We propose to use non-Gaussianities, especially the shape function of the bi- and trispectrum, to identify those models that are most likely responsible for inflation. We plan to use and improve upon a recently proposed mode decomposition retaining information of the full shape function and investigate the efficiency of the mode decomposition for constructing initial conditions for cosmological simulations.

• DFG Programme: Research Grants
• Participating Person: Dr. Thorsten J. Battefeld