Adiabatic and entropy perturbations propagation in a bouncing Universe

  title={Adiabatic and entropy perturbations propagation in a bouncing Universe},
  author={Patrick Peter and N. Pinto-Neto and Diego Gonzalez},
  journal={arXiv: High Energy Physics - Theory},
By studying some bouncing universe models dominated by a specific class of hydrodynamical fluids, we show that the primordial cosmological perturbations may propagate smoothly through a general relativistic bounce. We also find that the purely adiabatic modes, although almost always fruitfully investigated in all other contexts in cosmology, are meaningless in the bounce or null energy condition (NEC) violation cases since the entropy modes can never be neglected in these situations: the… 
Stochastic background of relic gravitons in a bouncing quantum cosmological model
The spectrum and amplitude of the stochastic background of relic gravitons produced in a bouncing universe is calculated. The matter content of the model consists of dust and radiation fluids, and
Observational signatures of a non-singular bouncing cosmology
We study a cosmological scenario in which inflation is preceded by a bounce. In this scenario, the primordial singularity, one of the major shortcomings of inflation, is replaced by a non-singular
Duality and scale invariant magnetic fields from bouncing universes
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,
Cosmological Perturbations on a Bouncing Brane
The cosmological perturbations on a bouncing brane are studied. The brane is moving inside a Klebanov–Strassler throat where the infrared region of the geometry is smoothly cut off. For an observer
Nonsingular cosmology with a scale-invariant spectrum of cosmological perturbations from Lee-Wick theory
We study the cosmology of a Lee-Wick type scalar field theory. First, we consider homogeneous and isotropic background solutions and find that they are nonsingular, leading to cosmological bounces.
Cross-correlations between scalar perturbations and magnetic fields in bouncing universes
Bouncing scenarios offer an alternative to the inflationary paradigm for the generation of perturbations in the early universe. Recently, there has been a surge in interest in examining the issue of
Generation of scale invariant magnetic fields in bouncing universes
We consider the generation of primordial magnetic fields in a class of bouncing models when the electromagnetic action is coupled non-minimally to a scalar field that, say, drives the background
Viable tensor-to-scalar ratio in a symmetric matter bounce
Matter bounces refer to scenarios wherein the universe contracts at early times as in a matter dominated epoch until the scale factor reaches a minimum, after which it starts expanding. While such
The tensor bi-spectrum in a matter bounce
Matter bounces are bouncing scenarios wherein the universe contracts as in a matter dominated phase at early times. Such scenarios are known to lead to a scale invariant spectrum of tensor
Bouncing alternatives to inflation
Abstract Although the inflationary paradigm is the most widely accepted explanation for the current cosmological observations, it does not necessarily correspond to what actually happened in the


The primordial universe : Les Houches, session LXXI, 28 June-23 July 1999 = L'univers primordial
The Universe at High Redshift.- Cosmological Parameters and Galaxy Formation.- A Short Course on Big Bang Nucleosynthesis.- The Cosmic Microwave Background: From Detector Signals to Constraints on
Cosmological Inflation and Large-Scale Structure
Quantum Fields in Curved Space
This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black hole
however (for it was the literal soul of the life of the Redeemer, John xv. io), is the peculiar token of fellowship with the Redeemer. That love to God (what is meant here is not God’s love to men)
Advanced Mathematical Methods
Preface Part I. Linear Algebra: 1. Vector spaces (revision) 2. Geometry in R 3. Matrices 4. Projections 5. Spectral theory 6. The upper triangular form 7. The tri-diagonal form 8. Inverses 9.
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