1995/05/09 by M. Gasperini, Massimo Giovannini, M. Giovannini +1 · 3 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #astro-ph #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.52.r6651
published as Phys.Rev.D52:6651-6655,1995 · 11 pages, LATEX
arxiv created 1995/05/09 · openalex publication_date 1995/12/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In the inflationary scenarios suggested by string theory, the vacuum fluctuations of the electromagnetic field can be amplified by the time evolution of the dilaton background, and can grow large enough to explain both the origin of the cosmic magnetic fields and of the observed CMB anisotropy. The normalization of the perturbation spectrum is fixed, and implies a relation between the perturbation amplitude at the COBE scale and the spectral index n. Working within a generic two-parameter family of backgrounds, a large scale anisotropy \ensuremathΔT/T\ensuremath≃10^\mathrm\ensuremath-5 is found to correspond to a spectral index in the range n\ensuremath≃1.11-1.17. \textcopyright 1995 The American Physical Society.