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Inflationary Attractor. Zong-Kuan Guo (advisor: Yuan-Zhong Zhang) Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080, P.R.China. Background. Standard Cosmology Inflationary Cosmology Initial Conditions for inflation. Outline.
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Inflationary Attractor Zong-Kuan Guo (advisor: Yuan-Zhong Zhang) Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100080, P.R.China
Background • Standard Cosmology • Inflationary Cosmology • Initial Conditions for inflation
Outline • Inflationary Cosmology • Tachyon Cosmology • Inflationary Attractor from Tachyonic Matter • Braneworld Cosmology • Inflationary Attractor in Braneworld Scenario • Conclusions
Inflationary Cosmology the Einstein-Hilbert action the Friedmann equation the equation of motion of the inflation field the energy density and pressure of a scalar field the conditon for inflation
Tachyon Cosmology the effective action of the tachyon field in the Born-Infeld form the Friedmann equation the evolution equation of the tachyon field the energy density and pressure of a tachyon field the condition for inflation
Inflationary Attractor from Tachyonic Matter Demonstrate: the Hamilton-Jacobi equations Consider a linear perturbation
Analysis: Potential the low-roll curve the potential-dominated region P the kinetic-energy-dominated region K
Phase portrait for the tachyon field with in the standard cosmology.
Phase portrait for the tachyon field with in the standard cosmology.
Braneworld Cosmology the action in the Randall-Sundrum II model the four-dimensional Einstein equations induced on the brane the modified Friedmann equation on the brane
Inflationary Attractor in Braneworld Scenario For a standard inflation, the evolution equation of the field and the modified Friedmann equation the Hamilton-Jacobi equations Consider a linear perturbation
Phase portrait for the scalar field with in the braneworld scenario.
Phase portrait for the scalar field with in the braneworld scenario.
Inflationary Attractor in Braneworld Scenario For a tachyon field, the evolution equation of the field and the modified Friedmann equation the Hamilton-Jacobi equations Consider a linear perturbation
Phase portrait for the tachyon field with in the braneworld scenario.
Phase portrait for the tachyon field with in the braneworld scenario.
Conclusions • Tachyon inflation possesses the attractor behavior in the standard cosmology. • Inflations driven by a scalar field or a tachyon field in the braneworld scenario possess the attractor behavior. • Initial kinetic terms decays morerapidly in the braneworld scenario than in the standard cosmology.
Thank you! Thank Yuan-Zhong Zhang, Rong-Gen Cai, Yun-Song Piao, Qing-Guo Huang, Hong-Sheng Zhang, Qi Guo and Xiu-Lian Wang for helpful discussions!