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اخترفیزیک و علوم فضایی 2012
جزئیات رویداد
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  • emergent universe with scalar (or tachyonic) field in higher derivative theory

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    • تاریخ ارائه: 1392/07/24
    • تاریخ انتشار در تی پی بین: 1392/07/24
    • تعداد بازدید: 1006
    • تعداد پرسش و پاسخ ها: 0
    • شماره تماس دبیرخانه رویداد: -
    we consider a spatially homogeneous and isotropic flat robertson-walker model filled with a scalar (or tachyonic) field minimally coupled to gravity in the framework of higher derivative theory. we discuss the possibility of the emergent universe with normal and phantom scalar fields (or normal and phantom tachynoic fields) in higher derivative theory. we find the exact solution of field equations in normal and phantom scalar fields and observe that the emergent universe is not possible in normal scalar field as the kinetic term is negative. however, the emergent universe exists in phantom scalar field in which the model has no time-like singularity at infinite past. the model evolves into an inflationary stage and finally admits an accelerating phase at late time. the equation of state parameter is found to be less than −1 in early time and tends to −1 in late time of the evolution. the scalar potential increases from zero at infinite past to a flat potential in late time. more precisely, we discuss the particular case for phantom field in detail. we also carry out a similar analysis in case of normal and phantom tachyonic field and observe that only phantom tachyonic field solution represents an emergent universe. we find that the coupling parameter of higher order correction affects the evolution of the emergent universe. the stability of solutions and their physical behaviors are discussed in detail.

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