FRW scalar-field cosmologies with fluid and curvature are organized by five parameter loci with explicit reduced normal forms, and a new arctan-slope variable extends the atlas to quadratic potentials.
Scaling Solutions in Robertson-Walker Spacetimes
4 Pith papers cite this work. Polarity classification is still indexing.
abstract
We investigate the stability of cosmological scaling solutions describing a barotropic fluid with $p=(\gamma-1)\rho$ and a non-interacting scalar field $\phi$ with an exponential potential $V(\phi)=V_0\e^{-\kappa\phi}$. We study homogeneous and isotropic spacetimes with non-zero spatial curvature and find three possible asymptotic future attractors in an ever-expanding universe. One is the zero-curvature power-law inflation solution where $\Omega_\phi=1$ ($\gamma<2/3,\kappa^2<3\gamma$ and $\gamma>2/3,\kappa^2<2$). Another is the zero-curvature scaling solution, first identified by Wetterich, where the energy density of the scalar field is proportional to that of matter with $\Omega_\phi=3\gamma/\kappa^2$ ($\gamma<2/3,\kappa^2>3\gamma$). We find that this matter scaling solution is unstable to curvature perturbations for $\gamma>2/3$. The third possible future asymptotic attractor is a solution with negative spatial curvature where the scalar field energy density remains proportional to the curvature with $\Omega_\phi=2/\kappa^2$ ($\gamma>2/3,\kappa^2>2$). We find that solutions with $\Omega_\phi=0$ are never late-time attractors.
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Exponential quintessence with an assumed kination epoch relaxes the dark energy fine-tuning problem by dozens of orders of magnitude relative to a cosmological constant.
For an exponential quintessence potential, an analytic formula links the current equation-of-state w_φ0 to the potential slope λ while enforcing prior radiation and matter domination, yielding the bound λ < 1.94 at Ω_φ0 = 0.685.
A review of string-inspired dynamical dark energy models claiming compatibility with DESI's hints of evolving dark energy under swampland constraints.
citing papers explorer
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Persistence and Transition Varieties in Scalar Field Cosmology
FRW scalar-field cosmologies with fluid and curvature are organized by five parameter loci with explicit reduced normal forms, and a new arctan-slope variable extends the atlas to quadratic potentials.
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Exponential Quintessence Model: Analytical Quantification of the Fine-Tuning Problem in Dark Energy
Exponential quintessence with an assumed kination epoch relaxes the dark energy fine-tuning problem by dozens of orders of magnitude relative to a cosmological constant.
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Exponential Quintessence: Analytic Relationship Between the Current Equation of State Parameter and the Potential Parameter
For an exponential quintessence potential, an analytic formula links the current equation-of-state w_φ0 to the potential slope λ while enforcing prior radiation and matter domination, yielding the bound λ < 1.94 at Ω_φ0 = 0.685.
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Breaking Free from the Swampland of Impossible Universes through the DESI Portal
A review of string-inspired dynamical dark energy models claiming compatibility with DESI's hints of evolving dark energy under swampland constraints.