On the Spectrum of Fluctuations in an Effective Field Theory of the Ekpyrotic Universe

Abstract

We consider the four-dimensional effective field theory which has been used in previous studies of perturbations in the Ekpyrotic Universe, and discuss the spectrum of cosmological fluctuations induced on large scales by quantum fluctuations of the bulk brane. By matching cosmological fluctuations on a constant energy density hypersurface we show that the growing mode during the very slow collapsing pre-impact phase couples only to the decaying mode in the expanding post-impact phase, and that hence no scale-invariant spectrum of adiabatic fluctuations is generated. Note that our conclusions may not apply to improved toy models for the Ekpyrotic scenario.

8 pages, few sentences added. Conclusions unchanged. Added references. Missing name added to Ref. 50

Cited by in corpus (149)

• Inflation Dynamics and Reheating
• Cosmology and Fundamental Physics with the Euclid Satellite
• The Pre-Big Bang Scenario in String Cosmology
• Towards a Nonsingular Bouncing Cosmology
• On the Generation of a Scale-Invariant Spectrum of Adiabatic Fluctuations in Cosmological Models with a Contracting Phase
• Bouncing Cosmologies: Progress and Problems
• Ekpyrotic and Cyclic Cosmology
• A Critical Review of Classical Bouncing Cosmologies
• New Ekpyrotic Cosmology
• Cosmology and Brane Worlds: A Review
• Lectures on string/brane cosmology
• Brane World Cosmology
• Kasner and Mixmaster behavior in universes with equation of state w \ge 1
• Density Perturbations in the Ekpyrotic Scenario
• Cosmology With Negative Potentials
• Designing Cyclic Universe Models
• A Nonsingular Cosmology with a Scale-Invariant Spectrum of Cosmological Perturbations from Lee-Wick Theory
• A smooth bouncing cosmology with scale invariant spectrum
• On the Construction of Nonsingular Pre-Big-Bang and Ekpyrotic Cosmologies and the Resulting Density Perturbations
• Suppressing CMB Quadrupole with a Bounce from Contracting Phase to Inflation
• Adiabatic and Isocurvature Perturbations for Multifield Generalized Einstein Models
• Primordial perturbations in a non singular bouncing universe model
• Conserved cosmological perturbations
• Cosmological perturbations through a simple bounce
• The cosmic gravitational wave background in a cyclic universe
• Rapidly-Varying Speed of Sound, Scale Invariance and Non-Gaussian Signatures
• Adiabatic perturbations in pre big bang models: matching conditions and scale invariance
• Cosmological Perturbations in a Big Crunch/Big Bang Space-time
• Density perturbations in generalized Einstein scenarios and constraints on nonminimal couplings from the Cosmic Microwave Background
• Perturbations in bouncing cosmologies: dynamical attractor vs scale invariance
• Passing through the bounce in the ekpyrotic models
• Primordial Perturbation in Horava-Lifshitz Cosmology
• Isocurvature perturbations in the Ekpyrotic universe
• A non inflationary model with scale invariant cosmological perturbations
• Perturbations in a non-singular bouncing Universe
• Conditions for Generating Scale-Invariant Density Perturbations
• Parametric amplification of metric fluctuations through a bouncing phase
• Assisted Contraction
• WMAP and Inflation
• Inflation versus Cyclic Predictions for Spectral Tilt
• The Cyclic Model Simplified
• Supersymmetric Galileons
• DBI Realizations of the Pseudo-Conformal Universe and Galilean Genesis Scenarios
• The Pseudo-Conformal Universe: Scale Invariance from Spontaneous Breaking of Conformal Symmetry
• Quantum Fields in a Big Crunch/Big Bang Spacetime
• Inflation with violation of the null energy condition
• Ekpyrotic collapse with multiple fields
• Cosmological perturbations across a curvature bounce
• On the Initial Conditions in New Ekpyrotic Cosmology
• Cosmological perturbations and the transition from contraction to expansion
• Curvature perturbations from ekpyrotic collapse with multiple fields
• A new duality relating density perturbations in expanding and contracting Friedmann cosmologies
• Thermal Fluctuations and Bouncing Cosmologies
• Non-linear Realizations of Conformal Symmetry and Effective Field Theory for the Pseudo-Conformal Universe
• Trans-Planckian Physics and the Spectrum of Fluctuations in a Bouncing Universe
• Defrosting in an Emergent Galileon Cosmology
• Scale-invariance in expanding and contracting universes from two-field models
• Note on the production of scale-invariant entropy perturbation in the Ekpyrotic universe
• On the "Causality Argument" in Bouncing Cosmologies
• Non-singular big-bounces and evolution of linear fluctuations
• Fluctuations in a Hořava-Lifshitz Bouncing Cosmology
• Shift Symmetry and Inflation in Supergravity
• Inflation with a Negative Cosmological Constant
• Curvatons in Supersymmetric Models
• From Satisfying to Violating the Null Energy Condition
• Generating Scale-Invariant Perturbations from Rapidly-Evolving Equation of State
• Scalar and Tensor Perturbations in DHOST Bounce Cosmology
• Proliferation in Cycle
• Vector Perturbations in a Contracting Universe
• Cosmological Perturbations Through a General Relativistic Bounce
• Scalar perturbations in regular two-component bouncing cosmologies
• Realizing Scale-invariant Density Perturbations in Low-energy Effective String Theory
• Dark Energy and the Return of the Phoenix Universe
• Spectra of primordial fluctuations in two-perfect-fluid regular bounces
• Comment on "Density perturbations in the ekpyrotic scenario"
• Cosmic Perturbations Through the Cyclic Ages
• The Primordial Perturbation Spectrum from Various Expanding and Contracting Phases
• Nonsingular Ekpyrotic Cosmology with a Nearly Scale-Invariant Spectrum of Cosmological Perturbations and Gravitational Waves
• Patch dualities and remarks on nonstandard cosmologies
• Study of a Class of Four Dimensional Nonsingular Cosmological Bounces
• Ekpyrotic Cosmology with a Zero-Shear S-Brane
• Collision of Domain Walls and Reheating of the Brane Universe
• Towards a Cosmological Dual to Inflation
• Regular two-component bouncing cosmologies and perturbations therein
• On Dualities Of Primordial Perturbation Spectra
• Global Fluctuation Spectra in Big Crunch/Big Bang String Vacua
• Modulated Perturbations from Instant Preheating after new Ekpyrosis
• Ekpyrotic loop quantum cosmology
• Adiabatic and entropy perturbations propagation in a bouncing Universe
• Cosmological Perturbations Across an S-brane
• Construction of nonsingular cosmological solutions in string theories
• Perturbations in a Bouncing Brane Model
• Large Adiabatic Scalar Perturbations in a Regular Bouncing Universe
• On the Transfer of Metric Fluctuations when Extra Dimensions Bounce or Stabilize
• Collision of Domain Walls in asymptotically Anti de Sitter spacetime
• Solution of a Braneworld Big Crunch/Big Bang Cosmology
• On the properties of the transition matrix in bouncing cosmologies
• Cyclic Inflation
• Scalar perturbations in conformal rolling scenario with intermediate stage
• Decoherence out of fire: Purity loss in expanding and contracting universes
• Unconventional Cosmology
• K-Bounce
• General solution for scalar perturbations in bouncing cosmologies
• Scale Invariance via a Phase of Slow Expansion
• Early Universe Dynamics in Semi-Classical Loop Quantum Cosmology
• Design of a Cyclic Multiverse
• Cosmological matching conditions
• Particle Production in Ekpyrotic Scenarios
• The curvaton as a Bose-Einstein condensate of chiral pseudo Nambu-Goldstone bosons
• Generalised perturbation equations in bouncing cosmologies
• Identification of perturbation modes and controversies in ekpyrotic perturbations
• Primordial Perturbations During a Slow Expansion
• Perturbations in a regular bouncing Universe
• Is the island universe model consistent with observations?
• String Propagation through a Big Crunch/Big Bang Transition
• Primordial power spectrum from a matter-Ekpyrotic bounce scenario in loop quantum cosmology
• Massive gravity and the suppression of anisotropies and gravitational waves in a matter-dominated contracting universe
• Strong Coupling Problem with Time-Varying Sound Speed
• No-Go theorems for ekpyrosis from ten-dimensional supergravity
• Cosmologies from higher-order string corrections
• Effective theory for close limit of two branes
• On the Effects due to a Decaying Cosmological Fluctuation
• Dark Energy Perturbations Revisited
• Large classical universes emerging from quantum cosmology
• Exact Tunneling Solutions in Minkowski Spacetime and a Candidate for Dark Energy
• The CST Bounce Universe model -- a parametric study
• Evolution of linear perturbations through a bouncing world model: Is the near Harrison-Zel'dovich spectrum possible via a bounce?
• Dynamics of Cosmological Perturbations and Reheating in the Anamorphic Universe
• From Big Crunch to Big Bang: A Quantum String Cosmology Perspective
• Island Cosmology in the Landscape
• Perturbations in Bouncing and Cyclic Models, a General Study
• Towards conformal cosmology
• Flow in Cyclic Cosmology
• Scalar Perturbation Spectra in an Emergent Cosmological Island
• Stochastic background of relic gravitons in a bouncing quantum cosmological model
• Topological defects: A problem for cyclic universes?
• Graviton production from extra dimensions
• Inflationary Cosmology: Theory and Phenomenology
• Big Bounce Baryogenesis
• Primordial Black Hole Formation in a Dust Bouncing Model
• Bouncing universes and their perturbations : a simple model revisited
• Entropic mechanisms with generalized scalar fields in the Ekpyrotic universe
• Non-local Matching Condition and Scale-invariant Spectrum in Bouncing Cosmology
• The general solution at large scale for second order perturbations in a scalar field dominated universe
• Warm Ekpyrosis
• Pseudo-conformal Universe: late-time contraction and generation of tensor modes
• On black holes in heterotic braneworlds
• Gravitational Leptogenesis in Bounce Cosmology
• Analytic Approximations for the Primordial Power Spectrum with Israel Junction Conditions