Seeds of large-scale anisotropy in string cosmology

Abstract

Pre-big bang cosmology predicts tiny first-order dilaton and metric perturbations at very large scales. Here we discuss the possibility that other -- more copiously generated -- perturbations may act, at second order, as scalar seeds of large-scale structure and CMB anisotropies. We study, in particular, the cases of electromagnetic and axionic seeds. We compute the stochastic fluctuations of their energy-momentum tensor and determine the resulting contributions to the multipole expansion of the temperature anisotropy. In the axion case it is possible to obtain a flat or slightly tilted blue spectrum that fits present data consistently, both for massless and for massive (but very light) axions.

27 pages, LATEX, one figure included using epsf

References in corpus (38)

• 4-Year COBE DMR Cosmic Microwave Background Observations: Maps and Basic Results
• Pre-Big-Bang in String Cosmology
• Elements of String Cosmology
• Primordial Magnetic Fields From String Cosmology
• Towards a non-singular pre-big bang cosmology
• Relic Gravitational Waves from String Cosmology
• Cosmic Temperature Fluctuations from Two Years of COBE DMR Observations
• The Graceful Exit Problem in String Cosmology
• Duality and Dilaton
• Twisting Classical Solutions in Heterotic String Theory
• Inflation Deflation and Frame-Independence in String Cosmology
• Dilaton Production in String Cosmology
• $O(d,d)$-Covariant String Cosmology
• Manifestly $O(d,d)$ Invariant Approach to Space-Time Dependent String Vacua
• A Model of Graceful Exit in String Cosmology
• Metric Perturbations in Dilaton-Driven Inflation
• Vacuum fluctuations in axion-dilaton cosmologies
• Towards a Singularity-Free Inflationary Universe?
• One-Loop Superstring Cosmology and the Non-Singular Universe
• Tree-level String Cosmology
• Graceful exit in quantum string cosmology
• Dilaton Contributions to the Cosmic Gravitational Wave Background
• Graceful Exit and Energy Conditions in String Cosmology
• Inhomogeneous Pre-Big Bang String Cosmology
• Peak and end point of the relic graviton background in string cosmology
• Pre-Big-Bang Inflation Requires Fine Tuning
• Axions and the Graceful Exit Problem in String Cosmology
• Back Reaction and Graceful Exit in String Inflationary Cosmology
• RMS Anisotropy in the COBE-DMR Four-Year Sky Maps
• Tensor perturbations in high-curvature string backgrounds
• Doppler Peaks in the Angular Power Spectrum of the Cosmic Microwave Background: A Fingerprint of Topological Defects
• Quantum Inhomogeneities in String Cosmology
• Classical Inhomogeneities in String Cosmology
• Singularity and exit problems in two-dimensional string cosmology
• Electromagnetic Origin of the CMB Anisotropy in String Cosmology
• Isocurvature and Adiabatic Fluctuations of Axion in Chaotic Inflation Models and Large Scale Structure
• Microwave Background Anisotropies from Scaling Seed Perturbations
• The fine tuning problem in pre-big-bang inflation

Cited by in corpus (38)

• Generating the curvature perturbation without an inflaton
• Gravitational Wave Experiments and Early Universe Cosmology
• The Pre-Big Bang Scenario in String Cosmology
• Adiabatic CMB perturbations in pre-big bang string cosmology
• Superstring Cosmology
• On the Generation of a Scale-Invariant Spectrum of Adiabatic Fluctuations in Cosmological Models with a Contracting Phase
• Cosmic Density Perturbations from Late-Decaying Scalar Condensations
• Adiabatic perturbations in pre big bang models: matching conditions and scale invariance
• Primordial magnetic fields from inflation?
• Correlated isocurvature perturbations from mixed inflaton-curvaton decay
• Inflation in string-inspired cosmology and suppression of CMB low multipoles
• Assisting pre-big bang phenomenology through short-lived axions
• Cosmological perturbation theory
• Non-Gaussianity from Symmetry
• Open and closed CDM isocurvature models contrasted with the CMB data
• Relativistic Modified Newtonian Dynamics from String Theory?
• Massless (pseudo-)scalar seeds of CMB anisotropy
• Constraints on pre-big bang parameter space from CMBR anisotropies
• Skewness as a probe of non-Gaussian initial conditions
• Cosmic Microwave Background anisotropies and extra dimensions in String Cosmology
• Superhorizon curvaton amplitude in inflation and pre-big bang cosmology
• Constraints on pre-big bang models for seeding large-scale anisotropy by massive Kalb-Ramond axions
• Anisotropic 'hairs' in string cosmology
• String-inspired cosmology
• Reheating and dangerous relics in pre-big bang string cosmology
• Inflation and initial conditions in the pre-big bang scenario
• CMB anisotropies from pre-big bang cosmology
• Blue Spectra of Kalb-Ramond Axions and Fully Anisotropic String Cosmologies
• Graviton production in non-inflationary cosmology
• Massive fermion production in nonsingular superstring cosmology
• Kalb-Ramond axion production in anisotropic string cosmologies
• Dark matter and baryogenesis in the Fermi-bounce curvaton mechanism
• Cosmological perturbation spectra from SL(4,R)-invariant effective actions
• Graviton production from extra dimensions
• Cold and Hot Dark Matter from a Single Nonthermal Relic
• Inflating, Warming Up, and Probing the Pre-Bangian Universe
• Weighing the string mass with the COBE data
• Quantum Gravity, Hydrodynamics and Emergent Cosmology: A Collection of Perspectives