منابع مشابه
A Braneworld Universe From Colliding Bubbles
Much work has been devoted to the phenomenology and cosmology of the socalled braneworld universe, where the (3+1)-dimensional universe familiar to us lies on a brane surrounded by a (4+1)-dimensional bulk spacetime that is essentially empty except for a negative cosmological constant and the various modes associated with gravity. For such a braneworld cosmology, the difficulty of justifying a ...
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The standard model of cosmology is based on the existence of homogeneous surfaces as the background arena for structure formation. Homogeneity underpins both general relativistic and modified gravity models and is central to the way in which we interpret observations of the cosmic microwave background (CMB) and the galaxy distribution. However, homogeneity cannot be directly observed in the gal...
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We compute the cosmological perturbations generated in the colliding bubble braneworld universe in which bubbles filled with five-dimensional antide Sitter space (AdS5) expanding within a five dimensional de Sitter space (dS5) or Minkowski space (M5) collide to form a (3+1) dimensional local brane on which the cosmology is virtually identical to that of the RandallSundrum model. The perturbatio...
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In this letter we present an idea which reconciles a homogeneous and isotropic Friedmann universe with a fractal distribution of galaxies. We use two observational facts: The flat rotation curves of galaxies and the (still debated) fractal distribution of galaxies with fractal dimension D = 2. Our idea can also be interpreted as a redefinition of the notion of bias.
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I critically discuss in a pedagogical and phenomenological way a few crucial tests challenging the recent claims by Pietronero and collaborators that there is no evidence from available galaxy catalogues that the Universe is actually homogeneous above a certain scale. In a series of papers, these authors assert that observations are consistent with a fractal distribution of objects extending to...
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ژورنال
عنوان ژورنال: Classical and Quantum Gravity
سال: 2004
ISSN: 0264-9381,1361-6382
DOI: 10.1088/0264-9381/21/4/013