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236
Matching RadiationDominated and MatterDominated Einsteinde Sitter Universes and an Application for Primordial Black Holes in Evolving Cosmological Backgrounds
, 2006
"... Abstract By matching across a surface of constant time, it is demonstrated that the spacetime for a radiationdominated Einsteinde Sitter universe can be directly matched to the spacetime for a matterdominated Einsteinde Sitter universe. Thus, this can serve as a model of a universe filled with ..."
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Abstract By matching across a surface of constant time, it is demonstrated that the spacetime for a radiationdominated Einsteinde Sitter universe can be directly matched to the spacetime for a matterdominated Einsteinde Sitter universe. Thus, this can serve as a model of a universe filled
Einsteinde Sitter Universe with (�
"... about 1.�2, the true spectral resolution is around 8 Å, consistent with the measured width of the spectral features. The average line profile, constructed from the Fe II lines above 6000 Å, appears unresolved. This implies that the absorbing clouds have a velocity dispersion of less than 100 km s �1 ..."
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about 1.�2, the true spectral resolution is around 8 Å, consistent with the measured width of the spectral features. The average line profile, constructed from the Fe II lines above 6000 Å, appears unresolved. This implies that the absorbing clouds have a velocity dispersion of less than 100 km s �1 in the rest frame. The observed BATSE gammaray fluence of GRB 990123 is 5.09 � 0.02 � 10 –4 erg cm –2 for energies above 20 keV (14). In Table 2 we give the luminosity distance and the inferred isotropic energy output in various cosmologies for z � 1.600. A lower limit to the isotropic energy release in gammarays alone is obtained in an
Holography in Radiationdominated Universe with a
, 2002
"... We discuss the holographic principle in a radiationdominated, closed FriedmannRobertsonWalker (FRW) universe with a positive cosmological constant. By introducing a cosmological Dbound on entropy of matter in the universe, we can write the Friedmann equation governing evolution of the universe i ..."
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Cited by 2 (0 self)
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We discuss the holographic principle in a radiationdominated, closed FriedmannRobertsonWalker (FRW) universe with a positive cosmological constant. By introducing a cosmological Dbound on entropy of matter in the universe, we can write the Friedmann equation governing evolution of the universe
Inhomogeneous Cosmological Models with Flat Slices Generated from the Einstein–de Sitter Universe
, 2001
"... A family of cosmological models is considered which in a certain synchronized system of reference possess flat slices t = const. They are generated from the EINSTEINDE SITTER universe by a suitable transformation. Under physically reasonable presumptions these transformed models fulfil certain ener ..."
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A family of cosmological models is considered which in a certain synchronized system of reference possess flat slices t = const. They are generated from the EINSTEINDE SITTER universe by a suitable transformation. Under physically reasonable presumptions these transformed models fulfil certain
Accepted to The Astrophysical Journal Constraints on the Redshift and Luminosity Distributions of Gamma Ray Bursts in an Einsteinde Sitter Universe
, 1997
"... Two models of the gamma ray burst population, one with a standard candle luminosity and one with a power law luminosity distribution, are χ 2fitted to the union of two data sets: the differential number versus peak flux distribution of BATSE’s long duration bursts, and the time dilation and energy ..."
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dilation factors are also corrected for energy stretching and similar effects. Within an Einsteinde Sitter cosmology, we place strong bounds on the evolution of the bursts, and these bounds are incompatible with a homogeneous population, assuming a power law spectrum and no luminosity evolution
Abstract Cosmological Black Holes as Models of Cosmological Inhomogeneities
, 2006
"... Since cosmological black holes modify the density and pressure of the surrounding universe, and introduce heat conduction, they produce simple models of cosmological inhomogeneities that can be used to study the eect of inhomogeneities on the universe's expansion. In this thesis, new cosmologi ..."
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spacetime, unlike previous solutions for cosmological black holes, which violate the energy conditions in some region of spacetime. In addition, it is demonstrated that radiationdominated and matterdominated Einsteinde Sitter universes can be directly matched across a hypersurface of constant time
The SelfOrganized de Sitter Universe
, 2008
"... We propose a theory of quantum gravity which formulates the quantum theory as a nonperturbative path integral, where each spacetime history appears with the weight exp (iS EH), with S EH the EinsteinHilbert action of the corresponding causal geometry. The path integral is diffeomorphisminvariant ( ..."
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invariant (only geometries appear) and backgroundindependent. The theory can be investigated by computer simulations, which show that a de Sitter universe emerges on large scales. This emergence is of an entropic, selforganizing nature, with the weight of the EinsteinHilbert action playing a minor role. Also
Inflation and de Sitter thermodynamics
 JCAP 0305
, 2003
"... Abstract. We consider the quaside Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quaside Sitter apparent horizon and set it equal to the change of the entropy (1/4 of the area) multiplied by the temperature, dE = ..."
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Cited by 5 (0 self)
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Abstract. We consider the quaside Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quaside Sitter apparent horizon and set it equal to the change of the entropy (1/4 of the area) multiplied by the temperature, dE
De Sitter and SchwarzschildDe Sitter According to Schwarzschild and De
 Sitter, JHEP 09(2003)009, arXiv:hepth/0308022 30 Maulik K. Parikh, Ivo Savonije, Erik Verlinde, Elliptic de Sitter Space: dS/ Z2, Phys.Rev. D67 (2003) 064005, arXiv:hepth/0209120
"... When de Sitter first introduced his celebrated spacetime, he claimed, following Schwarzschild, that its spatial sections have the topology of the real projective space IRP 3 (that is, the topology of the group manifold SO(3)) rather than, as is almost universally assumed today, that of the sphere S ..."
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Cited by 20 (14 self)
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When de Sitter first introduced his celebrated spacetime, he claimed, following Schwarzschild, that its spatial sections have the topology of the real projective space IRP 3 (that is, the topology of the group manifold SO(3)) rather than, as is almost universally assumed today, that of the sphere
Accelerating black holes in antide Sitter universe ∗
, 2002
"... A physical interpretation of the Cmetric with a negative cosmological constant Λ is suggested. Using a convenient coordinate system it is demonstrated that this class of exact solutions of Einstein’s equations describes uniformly accelerating (possibly charged) black holes in antide Sitter univers ..."
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A physical interpretation of the Cmetric with a negative cosmological constant Λ is suggested. Using a convenient coordinate system it is demonstrated that this class of exact solutions of Einstein’s equations describes uniformly accelerating (possibly charged) black holes in antide Sitter
Results 1  10
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236