منابع مشابه
Domain walls in a FRW universe.
We solve the equations of motion for a scalar field with domain wall boundary conditions in a Friedmann-Robertson-Walker (FRW) spacetime. We find (in agreement with Basu and Vilenkin) that no domain wall solutions exist in de Sitter spacetime for h ≡ H/m ≥ 1/2, where H is the Hubble parameter and m is the scalar mass. In the general FRW case we develop a systematic perturbative expansion in h t...
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Observational tests for the homogeneity of the Universe on large scales are reviewed. Assuming the Cosmological Principle we then estimate cosmological parameters by joint analysis of the Cosmic Microwave Background, Supernovae Ia, peculiar velocities, cluster abundance and redshift surveys. Our results are consistent with results obtained by other groups, suggesting a best-fit FRW Universe wit...
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Starting out with new deenitions for the gauge-invariant perturbations in energy density and particle number density, evolution equations for these quantities are derived which are manifestly gauge-invariant. In the case of vanishing pressure, these equations are identical to Poisson's equation. This fact is in contrast to what is found in earlier treatments based on other dee-nitions.
متن کاملComplete treatment of CMB anisotropies in a FRW universe
Wayne Hu, Uroš Seljak, Martin White, and Matias Zaldarriaga Institute for Advanced Study, School of Natural Sciences, Princeton, New Jersey 08540 Harvard Smithsonian Center For Astrophysics, Cambridge, Massachusetts 02138 Departments of Physics and Astronomy, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 Department of Physics, MIT, Cambridge, Massachusetts 02139 ~Received 1...
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We give a brief review of some aspects of inhomogeneous viscous fluids in a flat Friedmann-Robertson-Walker Universe. In general, it is pointed out that several fluid models may bring the future Universe evolution to become singular, with the appearance of the so-called Big Rip scenario. We investigate the effects of fluids coupled with dark matter in a de Sitter Universe, by considering severa...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2013
ISSN: 1550-7998,1550-2368
DOI: 10.1103/physrevd.88.105002