Phase-space analysis of the viscous fluid cosmological models in the coincident $f(Q)$ gravity

Abstract

In this article, we consider a newly proposed parameterization of the viscosity coefficient $\zeta$, specifically $\zeta ={\bar{\zeta }}_0{\Omega }_m^{s}H$, where ${\bar{\zeta }}_0=\frac{{\zeta }_0}{{\Omega }_{m_0}^s}$ within the coincident $f(Q)$ gravity formalism. We consider a non-linear function $f(Q)=-Q+\alpha Q^n$, where $\alpha$ and $n$ are arbitrary model parameters, which is a power-law correction to the STEGR scenario. We find an autonomous system by invoking the dimensionless density parameters as the governing phase-space variables. We discuss the physical significance of the model corresponding to the parameter choices $n=-1$ and $n=2$ along with the exponent choices $s=0,0.5$, and $1.05$. We find that model I shows the stable de-Sitter type or stable phantom type (depending on the choice of exponent $s$) behavior with no transition epoch, whereas model II shows the evolutionary phase from the radiation epoch to the accelerated de-Sitter epoch via passing through the matter-dominated epoch. Hence, we conclude that model I provides a good description of the late-time cosmology but fails to describe the transition epoch, whereas model II modifies the description in the context of the early universe and provides a good description of the matter and radiation era along with the transition phase.

Physics of the Dark Universe accepted version

References in corpus (17)

• Cosmological solutions and growth index of matter perturbations in $f(Q)$ gravity
• First evidence that non-metricity f(Q) gravity could challenge $\Lambda$CDM
• Viscous Cosmology for Early- and Late-Time Universe
• Testing $F(Q)$ gravity with redshift space distortions
• Black holes in $f(\mathbb{Q})$ Gravity
• Cosmology in $f(Q)$ gravity: A unified dynamical system analysis at background and perturbation levels
• New models and Big Bang Nucleosynthesis constraints in $f(Q)$ gravity
• Casimir Wormholes in Modified Symmetric Teleparallel Gravity
• Slow-roll inflation in $f(Q)$ non-metric gravity
• Late-time cosmology with phantom dark-energy in $f(Q)$ gravity
• Coincident f(Q) gravity: black holes, regular black holes and black bounces
• Minisuperspace quantum cosmology in $f(Q)$ gravity
• $f(Q)$-gravity and neutrino physics
• Energy condition bounds on $f(Q)$ model parameters in a curved FLRW universe
• Viscosity in modified gravity
• Remarks on cosmological bulk viscosity in different epochs
• The unified history of the viscous accelerating universe and phase transitions

Cited by in corpus (9)

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• Chameleon Mechanism in Scalar Nonmetricity Cosmology
• Emergent Universe in f(Q) gravity theories
• A generic dynamical system formulation for Bianchi-I cosmology with isotropic fluid in $f(Q)$ gravity
• Constraining viscous fluid models in $f(Q)$ gravity with data
• Late-time dynamics of dark energy EoS in symmetric teleparallel gravity
• Parameterized Deceleration in $f(Q,C)$ Gravity: A Logarithmic Approach
• Can an Extra Degree of Freedom in Scalar-Tensor Non-Metricity Gravity Account for the Evolution of the Universe?
• Beyond the Cosmological Constant: Breaking the Geometric Degeneracy of $f(Q)$ cosmology via Redshift-Space Distortions