Following the density perturbations through a bounce with AdS/CFT Correspondence. (arXiv:1701.04287v2 [hep-th] UPDATED)
<a href="http://arxiv.org/find/hep-th/1/au:+Ming_L/0/1/0/all/0/1">Lei Ming</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Zheng_T/0/1/0/all/0/1">Taifan Zheng</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Cheung_Y/0/1/0/all/0/1">Yeuk-Kwan E. Cheung</a>
A bounce universe model, known as the coupled-scalar-tachyon bounce (CSTB)
universe, has been shown to solve the Horizon, Flatness and Homogeneity
problems as well as the Big Bang Singularity problem. Furthermore a scale
invariant spectrum of primordial density perturbations generated from the phase
of pre-bounce contraction is shown to be stable against time evolution. In this
work we study the detailed dynamics of the bounce and its imprints on the scale
invariance of the spectrum. The dynamics of the gravitational interactions near
the bounce point may be strongly coupled as the spatial curvature becomes big.
There is no a prior reason to expect the spectral index of the primordial
perturbations of matter density can be preserved. By encoding the bounce
dynamics holographically onto the dynamics of dual Yang-Mills system while the
latter is weakly coupled, via the AdS/CFT correspondence, we can safely evolve
the spectrum of the cosmic perturbations with full control. In this way we can
compare the post-bounce spectrum with the pre-bounce one: in the CSTB model we
explicitly show that the spectrum of primordial density perturbations generated
in the contraction phase preserves its stability as well as scale invariance
throughout the bounce process.
A bounce universe model, known as the coupled-scalar-tachyon bounce (CSTB)
universe, has been shown to solve the Horizon, Flatness and Homogeneity
problems as well as the Big Bang Singularity problem. Furthermore a scale
invariant spectrum of primordial density perturbations generated from the phase
of pre-bounce contraction is shown to be stable against time evolution. In this
work we study the detailed dynamics of the bounce and its imprints on the scale
invariance of the spectrum. The dynamics of the gravitational interactions near
the bounce point may be strongly coupled as the spatial curvature becomes big.
There is no a prior reason to expect the spectral index of the primordial
perturbations of matter density can be preserved. By encoding the bounce
dynamics holographically onto the dynamics of dual Yang-Mills system while the
latter is weakly coupled, via the AdS/CFT correspondence, we can safely evolve
the spectrum of the cosmic perturbations with full control. In this way we can
compare the post-bounce spectrum with the pre-bounce one: in the CSTB model we
explicitly show that the spectrum of primordial density perturbations generated
in the contraction phase preserves its stability as well as scale invariance
throughout the bounce process.
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