Signature flips in time-varying $\Lambda (t)$ cosmological models with observational data

Abstract

In this study, we investigate signature flips within the framework of cosmological models featuring a time-varying vacuum energy term $\Lambda (t)$. Specifically, we consider the power-law form of $\Lambda =\alpha H^n$, where $\alpha$ and $n$ are constants. To constrain the model parameters, we use the MCMC technique, allowing for effective exploration of the model's parameters. We apply this approach to analyze 31 points of observational Hubble Data (OHD), 1048 points from the Pantheon data, and additional CMB data. We consider three scenarios: when $n$ is a free parameter (Case I), when $n=0$ (Case II), and when $n=1$ (Case III). In our analysis across all three cases, we observe that our model portrays the universe's evolution from a matter-dominated decelerated epoch to an accelerated epoch, as indicated by the corresponding deceleration parameter. In addition, we investigate the physical behavior of total energy density, total EoS parameter, and jerk parameter. Our findings consistently indicate that all cosmological parameters predict an accelerated expansion phase of the universe for all three cases ($q_0<0$, ${\omega }_0<-\frac{1}{3}$, $j_0>0$). Furthermore, our analysis reveals that the $Om(z)$ diagnostics for Cases I and III align with the quintessence region, while Case II corresponds to the $\Lambda$CDM model.

arXiv commentThe European Physical Journal C published version

References in corpus (79)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• emcee: The MCMC Hammer
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Dynamics of dark energy
• Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies
• Cosmological Constant - the Weight of the Vacuum
• The Case for a Positive Cosmological Lambda-term
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• An alternative to quintessence
• Generalized Chaplygin Gas, Accelerated Expansion and Dark Energy-Matter Unification
• A Dynamical Solution to the Problem of a Small Cosmological Constant and Late-time Cosmic Acceleration
• First results from the LUX dark matter experiment at the Sanford Underground Research Facility
• Statefinder -- a new geometrical diagnostic of dark energy
• Kinetically Driven Quintessence
• Information criteria for astrophysical model selection
• Accelerated expansion of the universe driven by tachyonic matter
• Coincident General Relativity
• Small Scale Cosmological Perturbations: An Analytic Approach
• Results from the Final Exposure of the CDMS II Experiment
• Measuring the Baryon Acoustic Oscillation scale using the SDSS and 2dFGRS
• Two new diagnostics of dark energy
• Cosmology in $f(Q)$ geometry
• Evolution of the Scale Factor with a Variable Cosmological Term
• Cosmography: Cosmology without the Einstein equations
• Hubble parameter measurement constraints on the redshift of the deceleration-acceleration transition, dynamical dark energy, and space curvature
• Cosmography in f(T)-gravity
• Hubble Parameter and Baryon Acoustic Oscillation Measurement Constraints on the Hubble Constant, the Deviation from the Spatially-Flat $\Lambda$cdm Model, The Deceleration-Acceleration Transition Redshift, and Spatial Curvature
• Phantom Field and the Fate of Universe
• Correcting Type Ia Supernova Distances for Selection Biases and Contamination in Photometrically Identified Samples
• Precision Cosmology? Not Just Yet
• Cosmographic analysis of the equation of state of the universe through Padé approximations
• First evidence of running cosmic vacuum: challenging the concordance model
• The fate of (phantom) dark energy universe with string curvature corrections
• The role of energy conditions in $f(R)$ cosmology
• Transition Redshift: New Kinematic Constraints from Supernovae
• Consequences on variable Lambda-models from distant Type Ia supernovae and compact radio sources
• An analysis of systematic effects in finite size scaling studies using the gradient flow
• Possible signals of vacuum dynamics in the Universe
• Energy conditions bounds on f(T) gravity
• Autonomous Dynamical System Approach for $f(R)$ Gravity
• A parametric reconstruction of the deceleration parameter
• Anisotropic nature of space-time in $f(Q)$ gravity
• Running vacuum against the $H_0$ and ${\sigma }_8$ tensions
• Dynamical dark energy versus $\Lambda =$const. in light of observations
• Observational constraints on two cosmological models of $f(Q)$ theory
• Cosmic acceleration and energy conditions in $\Lambda$CDM symmetric teleparallel $f(Q)$ gravity
• Running vacuum in quantum field theory in curved spacetime: renormalizing ${\rho }_{vac}$ without $\sim m^4$ terms
• Gaussian Process Estimation of Transition Redshift
• A new parametrization of Hubble parameter in $f(Q)$ gravity
• Late-time acceleration in $f\left(Q\right)$ gravity: Analysis and constraints in an anisotropic background
• Constraints on barotropic dark energy models by a new phenomenological $q(z)$ parameterization
• Running vacuum in the Universe: phenomenological status in light of the latest observations, and its impact on the ${\sigma }_8$ and $H_0$ tensions
• Can dark energy be expressed as a power series of the Hubble parameter?
• Looking for interactions in the cosmological dark sector
• Cosmological constraints on alternative model to Chaplygin fluid revisited
• Robust and model-independent cosmological constraints from distance measurements
• Acceleration of the universe: a reconstruction of the effective equation of state
• Stringy-Running-Vacuum-Model Inflation: from primordial Gravitational Waves and stiff Axion Matter to Dynamical Dark Energy
• Equation of state of the running vacuum
• Null Signal for the Cosmic Anisotropy in the Pantheon Supernovae Data
• Constant sound speed and its thermodynamical interpretation in $f(Q)$ gravity
• Dynamics and cosmological evolution in Λ-varying cosmology
• Interacting 3-form dark energy models: distinguishing interactions and avoiding the Little Sibling of the Big Rip
• Accelerating Universe scenario in anisotropic $f\left(Q\right)$ cosmology
• Testing dynamical vacuum models with CMB power spectrum from Planck
• Stability analysis of anisotropic Bianchi type-I cosmological model in teleparallel gravity
• Running vacuum in QFT in FLRW spacetime: The dynamics of ${\rho }_{\mathrm{vac}}(H)$ from the quantized matter fields
• Constraining the anisotropy of the Universe via Pantheon supernovae sample
• Confronting the relaxation mechanism for a large cosmological constant with observations
• Dark sector interactions and the curvature of the Universe in light of Planck's 2018 data
• A New $Om(z)$ Diagnostic of Dark Energy in General Relativity Theory
• Cosmological model with decaying vacuum energy law from principles of quantum mechanics
• Solving the $H_0$ tension in $f(T)$ Gravity through Bayesian Machine Learning
• The dynamics of matter bounce cosmology in Weyl-type $f(Q,T)$ gravity
• Cosmological Consequences of a Variable Cosmological Constant Model
• Geometrical Origin of the Cosmological Constant
• Nonsingular Cosmology from an Interacting Vacuum
• Viscous coupled fluids in terms of a log-corrected equation of state

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