Cosmographic analysis of sign-switching dark energy

Abstract

Inspired by the well-studied ${\Lambda }_{\mathrm{s}}$CDM model, we propose and investigate a class of dynamical dark energy models that evolve from a negative cosmological constant, transitioning to a positive value at low redshifts. Specifically, we introduce a dark energy framework based on a generalised ladder-step function for the cosmological constant. Furthermore, we present two additional models in which the cosmological constant undergoes a smooth sign change at a specified redshift. We provide a detailed discussion of the construction and theoretical properties of these models, analysing their background cosmological evolution using a cosmographic approach and the statefinder hierarchy parameters. Our results are compared with those obtained for the standard $\Lambda$CDM and ${\Lambda }_{\mathrm{s}}$CDM models. We also perform a careful analysis of the types of singularities that may arise in these models due to a sign change in the cosmological constant. Notably, we show that a continuous sign change removes the sudden singularity present in the ${\Lambda }_{\mathrm{s}}$CDM model, replacing it with a milder $w$-singularity.

Version accepted in PRD. Physical discussion improved and references added. 20 pages, 6 figures, REVTeX 4.2

References in corpus (34)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• In the Realm of the Hubble tension $-$ a Review of Solutions
• Dark torsion as the cosmic speed-up
• Modified teleparallel gravity: inflation without inflaton
• Challenges for $\Lambda$CDM: An update
• Imperfect Dark Energy from Kinetic Gravity Braiding
• Horndeski theory and beyond: a review
• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Cosmography of f(R) gravity
• Model independent evidence for dark energy evolution from Baryon Acoustic Oscillations
• Modified Gravity and Cosmology: An Update by the CANTATA Network
• Neutrino mass from Cosmology
• The Hubble series: Convergence properties and redshift variables
• Classification of cosmological milestones
• Observational constraints on cosmological solutions of $f(Q)$ theories
• Dark energy from the string axiverse
• Relaxing cosmological tensions with a sign switching cosmological constant
• Relaxing cosmological tensions with a sign switching cosmological constant: Improved results with Planck, BAO, and Pantheon data
• Barotropic index w-singularities in cosmology
• Cosmic chronometers to calibrate the ladders and measure the curvature of the Universe. A model-independent study
• Simple-graduated dark energy and spatial curvature
• Composite Dark Energy and the Cosmological Tensions
• Cosmological constraints on ${\Lambda }_{\mathrm{s}}$CDM scenario in a type II minimally modified gravity
• Anti-de Sitter $\to$ de Sitter transition driven by Casimir forces and mitigating tensions in cosmological parameters
• From infinite to infinitesimal: Using the Universe as a dataset to probe Casimir corrections to the vacuum energy from fields inhabiting the dark dimension
• Transition dynamics in the ${\Lambda }_{\mathrm{s}}$CDM model: Implications for bound cosmic structures
• Mapping the ${\Lambda }_{\mathrm{s}}$CDM scenario to $f(T)$ modified gravity: Effects on structure growth rate
• Non-parametric reconstruction of cosmological observables using Gaussian Processes Regression
• Thin-wall vacuum decay in the presence of a compact dimension meets the $H_0$ and $S_8$ tensions
• Linear matter density perturbations in the ${\Lambda }_{\mathrm{s}}$CDM model: Examining growth dynamics and addressing the $S_8$ tension
• Dark energy with a shift-symmetric scalar field: obstacles, loophole hunting and dead ends
• Phantom attractors in Kinetic Gravity Braiding theories: a dynamical system approach
• Relaxing cosmological constraints on current neutrino masses

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