Cosmological Perturbations Through a Simple Bounce

By L. Allen, D. Wands. 2004

146 citations recorded by the source corpus.

We present a 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 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/5e2cc5db07f308979ac704d04b5ef1023fb5a27e

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Citations in the corpus

Bouncing Cosmologies: Progress and Problems (2016, background): “[133] showed that during the collapse phase, one finds r = 8λ(2).”
Non-singular cosmology in a model of non-relativistic gravity (2009, methodology): “The scenario of bouncing cosmology has been investigated in models motivated by various approaches to quantum gravity [18–23], and analyzed using effective field techniques by introducing energy-condition-violating matters [11, 24–26], while the generation of perturbation was studied in [27–34] (and”
Matter bounce in Horava-Lifshitz cosmology (2009, background): “As realized in [14, 15, 16], perturbations which start out as quantum vacuum fluctuations and exit the Hubble radius during a matter-dominated phase of contraction acquire a scale-invariant spectrum.”
Nonsingular cosmology with a scale-invariant spectrum of cosmological perturbations from Lee-Wick theory (2008, background): “The second way is realized in the case of a matter-dominated contraction, a possibility already pointed out in [11] (see also [47]).”