Generation of Curvature Perturbations with Extra Anisotropic Stress

Abstract

We study the evolution of curvature perturbations and the cosmic microwave background (CMB) power spectrum in the presence of an hypothesized extra anisotropic stress which might arise, for example, from the dark radiation term in brane-world cosmology. We evolve the scalar modes of such perturbations before and after neutrino decoupling and analyze their effects on the CMB spectrum. A novel result of this work is that the cancellation of the neutrino and extra anisotropic stress could lead to a spectrum of residual curvature perturbations which is similar to the observed CMB power spectrum. This implies a possible additional consideration in the determination of cosmological parameters from the CMB analysis.

13 pages, 2 figures; improved discussion

References in corpus (10)

• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• CMB anisotropies from primordial inhomogeneous magnetic fields
• Effects of a Primordial Magnetic Field on Low and High Multipoles of the CMB
• The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies
• CMB anisotropies due to cosmological magnetosonic waves
• Tight coupling expansion and fully inhomogeneous magnetic fields
• Entropy perturbations and large-scale magnetic fields
• Constraints on the Primordial Magnetic Field from ${\sigma }_8$
• Neutrino mass effects on vector and tensor CMB anisotropies in the presence of a primordial magnetic field

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