Tuesday, May 15, 2012

1110.5392 (Yoshinobu Habara et al.)

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

Yoshinobu Habara, Hikaru Kawai, Masao Ninomiya, Yasuhiro Sekino
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.
View original: http://arxiv.org/abs/1110.5392

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