2017/08/22 by Robert Brandenberger, Guilherme Franzmann, Qiuyue Liang · 2 citations
Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Cosmological model #Cosmology #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Geometry #Inflation (cosmology) #Mathematical physics #Parametrization (atmospheric modeling) #Physics #Quantum mechanics #Relationship between string theory and quantum field theory #Scalar (mathematics) #Scalar field #Sign (mathematics) #Spectral index #Spectral line #String (physics) #String cosmology #Theoretical physics #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.96.123513
published as Phys. Rev. D 96, 123513 (2017) · 6 pages, 3 figures
arxiv created 2017/08/22 · openalex publication_date 2017/12/12 · arxiv updated 2017/12/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We compute the running of the spectrum of cosmological perturbations in string gas cosmology, making use of a smooth parametrization of the transition between the early Hagedorn phase and the later radiation phase. We find that the running has the same sign as in simple models of single scalar field inflation. Its magnitude is proportional to (1\ensuremath-ns) (ns being the slope index of the spectrum), and it is thus parametrically larger than for inflationary cosmology, where it is proportional to (1\ensuremath-ns)2.