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arXiv · 1110.5392

Possible origin of CMB temperature fluctuations: Vacuum fluctuations of Kaluza-Klein and string states during inflationary era

Yoshinobu Habara·Hikaru Kawai·Masao Ninomiya·Yasuhiro Sekino
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Abstract

We point out that the temperature fluctuations of cosmic microwave background (CMB) can be generated in a way that is different from the one usually assumed in slow-roll inflation. Our mechanism is based on vacuum fluctuations of fields which are at rest at the bottom of the potential, such as Kaluza-Klein modes or string excited states. When there are a large number (typically of order $N\sim 10^{14}$) of fields with small mass in unit of Hubble parameter during the inflationary era, this effect can give significant contributions to the CMB temperature fluctuations. This number $N$ makes it possible to enhance scalar perturbation relative to tensor perturbation. Comparison with the observed amplitudes suggests that models with string scale of order $10^{-5}$ of 4D Planck scale are favorable.

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Yoshinobu Habara, Hikaru Kawai, Masao Ninomiya, Yasuhiro Sekino. 2012-05-12. Possible origin of CMB temperature fluctuations: Vacuum fluctuations of Kaluza-Klein and string states during inflationary era. https://doi.org/10.1103/physrevd.85.104027

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