Results 21 to 30 of about 197,098 (270)
Homogeneous cosmologies with a cosmological constant [PDF]
Physical Review D, 1999 Spatially homogeneous cosmological models with a positive cosmological constant are investigated, using dynamical systems methods. We focus on the future evolution of these models. In particular, we address the question whether there are models within this class that are de Sitter-like in the future, but are tilted.
Goliath, Martin, Ellis, George F. R.
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Black branes with cosmological constant
Journal of High Energy Physics, 2022 We study neutral black branes with flat and curved worldvolumes in the presence of a negative cosmological constant. We reduce the equations governing the dynamics of such objects to one second-order ODE and perform various asymptotic expansions of the ...
Rhucha Deshpande, Oleg Lunin
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Gauge-dependent cosmological constant [PDF]
Classical and Quantum Gravity, 2004 When the cosmological constant of spacetime is derived from the 5D induced-matter theory of gravity, we show that a simple gauge transformation changes it to a variable measure of the vacuum which is infinite at the big bang and decays to an astrophysically-acceptable value at late epochs.
Mashhoon, Bahram, Wesson, Paul S.
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Cosmological constant from decoherence [PDF]
Classical and Quantum Gravity, 2011 We address the issue why a cosmological constant (dark energy) possesses a small positive value instead of being zero. Motivated by the cosmic landscape picture, we mimic the dark energy by a scalar field with potential wells and show that other degrees of freedom interacting with it can localize this field by decoherence in one of the wells.
Kiefer, Claus +2 more
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Inflation and cosmological constant [PDF]
Physica Scripta, 2021 Abstract In construction of an inflationary model, one usually assumes that the matter sector of the gravitational action is minimally coupled to the background. It means that the matter (inflaton) part of the action is coupled with the same metric of the gravitational part.
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Dark matter from torsion in Friedmann cosmology
European Physical Journal C: Particles and Fields, 2022 A cosmological model in an Einstein–Cartan framework endowed with torsion is studied. For a torsion function assumed to be proportional to Hubble expansion function, namely $$\phi =-\alpha H$$ ϕ = - α H , the contribution of torsion function as a dark ...
S. H. Pereira +3 more
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Loop quantum gravity and cosmological constant
Physics Letters B, 2021 A one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as special cases. The
Xiangdong Zhang, Gaoping Long, Yongge Ma
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The cosmological constant in supergravity
European Physical Journal C: Particles and Fields, 2018 We propose a supersymmetrisation of the cosmological constant in ordinary $$N=1$$ N=1 supergravity that breaks supersymmetry spontaneously by a constant Fayet-Iliopoulos (FI) term associated to a U(1) symmetry.
I. Antoniadis +3 more
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Universe, 2020 The stage of a super-early (primordial) scale-invariant Universe is considered on the basis of the Poincaré–Weyl gauge theory of gravity in a Cartan–Weyl space-time. An approximate solution has been found that demonstrates an inflationary behavior of the
Ol’ga Babourova, Boris Frolov
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Cosmology with varying constants [PDF]
Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 2001 14 pages, no figures. Essay to appear in Phil. Trans. Roy. Soc. Lond. A Triennial Series (Christmas 2002 Issue)
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