An Einstein-Cartan ekpyrotic model with a steep-to-plateau scalar potential supports a torsion-driven nonsingular bounce in homogeneous contraction without chaotic behavior in the explored parameter space.
Inflationary Universe with Anisotropic Hair
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
We study an inflationary scenario with a vector field coupled with an inflaton field and show that the inflationary universe is endowed with anisotropy for a wide range of coupling functions. This anisotropic inflation is a tracking solution where the energy density of the vector field follows that of the inflaton field irrespective of initial conditions. We find a universal relation between the anisotropy and a slow-roll parameter of inflation. Our finding has observational implications and gives a counter example to the cosmic no-hair conjecture.
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In asymptotically safe gravity, radiation-filled Bianchi-I cosmologies show quantum corrections that soften anisotropy, while magnetic fields lead to persistent Kasner anisotropy without Lambda but isotropic de Sitter decay with nonzero Lambda.
In kinetically coupled vector inflation, the bispectrum in the large-h regime exhibits competing local and flattened non-Gaussian signals with distinct h scalings that distinguish vector-supported dynamics.
Including spectral running α_s, β_s and self-interacting dark radiation relaxes the ACT DR6 bound on ΔN_eff to <0.58 and lowers the Hubble tension to 2.2σ with three extra parameters.
citing papers explorer
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Dynamical systems analysis of an Einstein-Cartan ekpyrotic nonsingular bounce cosmology
An Einstein-Cartan ekpyrotic model with a steep-to-plateau scalar potential supports a torsion-driven nonsingular bounce in homogeneous contraction without chaotic behavior in the explored parameter space.
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Bianchi-I Cosmology with Radiation in Asymptotically Safe Gravity
In asymptotically safe gravity, radiation-filled Bianchi-I cosmologies show quantum corrections that soften anisotropy, while magnetic fields lead to persistent Kasner anisotropy without Lambda but isotropic de Sitter decay with nonzero Lambda.
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Inflation with vector fields revisited: non-Gaussianities
In kinetically coupled vector inflation, the bispectrum in the large-h regime exhibits competing local and flattened non-Gaussian signals with distinct h scalings that distinguish vector-supported dynamics.
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The End of the First Act: Spectral Running, Interacting Dark Radiation, and the Hubble Tension in Light of ACT DR6 Data
Including spectral running α_s, β_s and self-interacting dark radiation relaxes the ACT DR6 bound on ΔN_eff to <0.58 and lowers the Hubble tension to 2.2σ with three extra parameters.