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Exact Cosmological Solutions of 4D String Gravity in the String Frame

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 نشر من قبل Yongsung Yoon
 تاريخ النشر 2013
  مجال البحث فيزياء
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 تأليف Yongsung Yoon




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We have discussed a particular class of exact cosmological solutions of the 4-dimensional low energy string gravity in the string frame. In the vacuum without matter and the 2-form fields, the exact cosmological solutions always give monotonically shrinking universes if the dilaton field is not a constant. However, in the presence of the 2-form fields and/or the radiation-like fluid in the string frame, the exact cosmological solutions show a minimum size of the universe in the evolution, but with an initial cosmological curvature singularity in the string frame.



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