Following the primordial perturbations through a bounce with AdS/CFT correspondence

Ming, Lei; Zheng, Taifan; Cheung, Yeuk-Kwan E.

doi:10.1140/epjc/s10052-018-6228-8

Cited by 2 publications

(4 citation statements)

References 79 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently an interesting attempt is made to use AdS/CFT correspondence to study the evolution of matter through the bounce point [46] which is inspired by an earlier attempt of using AdS/CFT to study cosmic singularity in the bound universe [45]. Pioneer works on studying AdS singularity can be found in [47][48][49][50][51][52][53][54], together with earlier initiatives of using AdS/CFT to study cosmic singularities [55][56][57][58][59][60][61][62][63][64][65][66].…”

Section: Discussionmentioning

confidence: 99%

The CST bounce universe model — A parametric study

Cheung

Song

et al. 2018

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

A bounce universe model with a scale-invariant and stable spectrum of primordial density perturbations was constructed using a consistent truncation of the D-brane dynamics from Type IIB string theory. A coupling was introduced between the tachyon field and the adjoint Higgs field on the D3-branes to lock the tachyon at the top of its potential hill and to model the bounce process, which is known as the Coupled Scalar and Tachyon Bounce (CSTB) Universe. The CSTB model has been shown to be ghost free, and it fulfils the null energy condition; in addition, it can also solve the Big Bang cosmic singularity problem. In this paper we conduct an extensive follow-up study of the parameter space of the CSTB model. In particular we are interested in the parameter values that can produce a single bounce to arrive at a radiation-dominated universe. We further establish that the CSTB universe is a viable alternative to inflation, as it can naturally produce a sufficient number of e-foldings in the locked inflation epoch and in the post-bounce expansion to overcome the four fundamental limitations of the Big Bang cosmology, which are flatness, horizon, homogeneity and singularity, resulting in a universe of the current size.bounce universe, big bang singularity, tachyon inflation, flatness and horizon problems PACS number(s): 11.25. Uv, 11.25.Mj, 11.25.Wx, 98.80.k, 98.80.Cq

show abstract

Section: Discussionmentioning

confidence: 99%

The CST bounce universe model — A parametric study

Cheung

Song

et al. 2018

Sci. China Phys. Mech. Astron.

View full text Add to dashboard Cite

show abstract

“…Care has been taken to compute the implicit time dependence in the k-modes as they exit their effective horizon at different times. The final spectrum of primordial density perturbations is shown to be scale invariant as well as stable against time evolution [37,42].…”

Section: The Primordial Tensor Perturbations In a Simplified Bouncementioning

confidence: 96%

“…A scale invariant and stable spectrum of primordial matter density perturbations is produced during the contraction phase [37]. The spectrum of the scalar perturbations is then evolved through the bounce; and its scale invariance and stability are shown to be unaffected by the dynamics of the potentially strong gravity during the bounce process via an AdS/CFT analysis [42]. The rest of this paper is devoted to the computation of the tensor modes of metric perturbations.…”

Section: The Dynamics Of Tensor Perturbations In the Cstb Universementioning

confidence: 99%

“…As Hubble parameter has time dependence different k-mode exits the horizon at different times. Only when this implicit time dependence is properly taken in account that one can establish the overall time dependence and scale dependence in the final power spectrum of the scalar perturbations in the metric [37,42,51]. Let us recall that in the CST bounce universe perturbations of the matter field δT obey the equation at super-Hubble scales,…”

Section: )mentioning

confidence: 99%

See 1 more Smart Citation

Primordial gravitational waves spectrum in the Coupled-Scalar-Tachyon Bounce Universe

Zhang

Cheung

2020

Eur. Phys. J. C

Self Cite

View full text Add to dashboard Cite

We derive in detail the equations of motion for the tensorial modes of primordial metric perturbations in the Coupled-Scalar-Tachyon Bounce Universe. We solve for the gravitational wave equations in the pre-bounce contraction and the post-bounce expansion epochs. To match the solutions of the tensor perturbations, we idealise the bounce process yet retaining the essential physical properties of the bounce universe. We put forward two matching conditions: one ensures the continuity of the gravitational wave functions and the other respects the symmetric nature of the bounce dynamics. The matching conditions connect the two independent modes of gravitational waves solutions before and after the bounce. We further analyse the scale dependence and time dependence of the gravitational waves spectra in the bounce universe and compare them with the primordial spectrum in the single field inflation scenario. We discuss the implications to early universe physics and present model independent observational signatures extracted from the bounce universe.

show abstract

Following the primordial perturbations through a bounce with AdS/CFT correspondence

Cited by 2 publications

References 79 publications

The CST bounce universe model — A parametric study

The CST bounce universe model — A parametric study

Primordial gravitational waves spectrum in the Coupled-Scalar-Tachyon Bounce Universe

Contact Info

Product

Resources

About