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Microscopic Theories for Holographic Dark Energy

Zeynizadeh, Sarang | 2016

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 48378 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Nouri-Zonoz, Mohammad; Golshani, Mehdi
  7. Abstract:
  8. Acceleration of the universe is one of the most challenging conundrum of contemporary physics. One of the leading approach to this conundrum is introducing a new component in Einstein’s equations which is called the dark energy. Dark energy models which their’s dynamics are dictated by holographic principle, are called holographic dark energy. Essentially,the constraint implied by the holographic principle is a macroscopic constraint. In consequence, the constraint gives no informations about microscopic aspects of dark energy. To understand the nature of the holographic dark energy, we need a microscopic theory from which we can extract the behaviors of holographic dark energy. It can be shown that many of the holographic dark energy models are equivalent to the quintessence dark energy with an exponential potential. Incidentally,there is a scale invariant version of the extended standard model of particle physics with an exponential potential. This model is called Higgs-dilaton model. Due to this correspondence, Higgs-dilaton model can be used as the origin of holographic dark energy. However, this model suffers from two problems. One of them is metastability of Higgs potential and the other one is it’s small value prediction of the tensor to scalar perturbation ratio. Here we study the Higgs-dilaton model under general initial conditions and we show that in the presence of finite temperature effects and for some initial conditions, the problems of this model can be solved
  9. Keywords:
  10. Holographic Dark Energy ; Higgs-Dilaton Cosmology ; Higgs Potential Metastability ; Non-Bunch-Davies Vacuum

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