Propagation of adiabatic and entropy perturbations in a bouncing universe

Peter, Patrick; Pinto-Neto, Nelson; Gonzalez, Diego A.

doi:10.1088/1475-7516/2003/12/003

Cited by 39 publications

(22 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several authors have studied the evolution of perturbations through a bounce using some analytic form for the background scale factor [27][28][29] and/or the evolution equations for perturbations [25]. But this has lead to apparently contradictory results depending on which functions are assumed to have a smooth regular form [25].…”

Section: Introductionmentioning

confidence: 99%

Cosmological perturbations through a simple bounce

2004

View full text Add to dashboard Cite

We present a detailed study of a simple scalar field model that yields non-singular cosmological solutions. We study both the qualitative dynamics of the homogeneous and isotropic background and the evolution of inhomogeneous linear perturbations. We calculate the spectrum of perturbations generated on super-Hubble scales during the collapse phase from initial vacuum fluctuations on small scales and then evolve these numerically through the bounce. We show there is a gauge in which perturbations remain well-defined and small throughout the bounce, even though perturbations in other commonly used gauges become large or ill-defined. We show that the comoving curvature perturbation calculated during the collapse phase provides a good estimate of the resulting large scale adiabatic perturbation in the expanding phase while the Bardeen metric potential is dominated by what becomes a decaying mode after the bounce. We show that a power-law collapse phase with scale factor proportional to $(-t)^{2/3}$ can yield a scale-invariant spectrum of adiabatic scalar perturbations in the expanding phase, but the amplitude of tensor perturbations places important constraints on the allowed initial conditions.Comment: 25 pages, 15 figures, latex with revtex. v2: missing factor of 2 included in tensor-scalar ratio, other minor changes and references added. v3: version to appear in PR

show abstract

Section: Introductionmentioning

confidence: 99%

Cosmological perturbations through a simple bounce

2004

View full text Add to dashboard Cite

show abstract

“…However as we will now show, this fact does not sign an instability of these models [16,17], but simply indicates that entropy perturbations cannot be neglected at the NEC transition time.…”

Section: The Evolution Of Cosmological Perturbations On Bouncing Mod-mentioning

confidence: 79%

Perturbations in Bouncing Cosmological Models

Pinto-Neto

2004

Int. J. Mod. Phys. D

View full text Add to dashboard Cite

show abstract

“…A reasonably popular alternative are bouncing models wherein the universe undergoes a period of contraction until the scale factor attains a minimum value, after which it begins to expand (see, for instance, Refs. [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65], and the following reviews [66][67][68][69]). Such bouncing scenarios provide an alternative to inflation to overcome the horizon problem.…”

Section: Introductionmentioning

confidence: 99%

Duality and scale invariant magnetic fields from bouncing universes

2016

View full text Add to dashboard Cite

Recently, we had numerically shown that, for a non-minimal coupling that is a simple power of the scale factor, scale invariant magnetic fields arise in a class of bouncing universes. In this work, we {\it analytically} evaluate the spectrum of magnetic and electric fields generated in a sub-class of such models. We illustrate that, for cosmological scales which have wavenumbers much smaller than the wavenumber associated with the bounce, the shape of the spectrum is preserved across the bounce. Using the analytic solutions obtained, we also illustrate that the problem of backreaction is severe at the bounce. Finally, we show that the power spectrum of the magnetic field remains invariant under a two parameter family of transformations of the non-minimal coupling function.Comment: v1: 17 pages, 5 figures; v2: 14 pages, 5 figures, bouncing model details and discussion extended, references added, to appear in Phys. Rev.

show abstract

Propagation of adiabatic and entropy perturbations in a bouncing universe

Cited by 39 publications

References 52 publications

Cosmological perturbations through a simple bounce

Cosmological perturbations through a simple bounce

Perturbations in Bouncing Cosmological Models

Duality and scale invariant magnetic fields from bouncing universes

Contact Info

Product

Resources

About