f(R) Gravity in an Ellipsoidal Universe

Abstract

We propose a new model of cosmology based on an anisotropic background and a specific $f(R)$ theory of gravity. It is shown that field equations of $f(R)$ gravity in a Bianchi type I background give rise to a modified Friedmann equation. This model contains two important parameters: $\gamma$ and $\delta$. We, thus, simply call our model $\gamma \delta$CDM. It is distinguished in two important aspects from the $\Lambda$CDM model: firstly, the contribution of different energy densities to the Hubble parameter are weighted with different weights, and then, dependence of energy densities to redshift is modified as well. This unorthodox relation of energy content to Hubble parameter brings forth a new way of interpreting the cosmological history. This solution does not allow the existence of a cosmological constant component, however, a dark energy contribution with dependence on redshift is possible. We tested observational relevance of the new solution by best fitting to different data sets. We found that our model could accommodate the idea of cosmological coupling of black holes.

arXiv comment20 pages, 4 figures, 2 tables. v2: Prior choices are explained. New references added. v3: New references and further comments added. v4: Data analysis is repeated with larger data sets. Conclusions are unchanged. New references added. Final version

References in corpus (94)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• f(R) Theories Of Gravity
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• f(R) theories
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km/s/Mpc Uncertainty from the Hubble Space Telescope and the SH0ES Team
• Baryonic Features in the Matter Transfer Function
• In the Realm of the Hubble tension $-$ a Review of Solutions
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory
• The Pantheon+ Analysis: Cosmological Constraints
• Constraints on the redshift dependence of the dark energy potential
• Tensions between the Early and the Late Universe
• A 6% measurement of the Hubble parameter at $z\sim 0.45$: direct evidence of the epoch of cosmic re-acceleration
• H0LiCOW XIII. A 2.4% measurement of $H_0$ from lensed quasars: $5.3\sigma$ tension between early and late-Universe probes
• Cosmic Chronometers: Constraining the Equation of State of Dark Energy. I: H(z) Measurements
• Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z$\sim$2
• Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers
• Constraining Cosmological Parameters Based on Relative Galaxy Ages
• The Pantheon+ Analysis: The Full Dataset and Light-Curve Release
• Challenges for $\Lambda$CDM: An update
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectrum
• The Carnegie-Chicago Hubble Program. VIII. An Independent Determination of the Hubble Constant Based on the Tip of the Red Giant Branch
• Cosmological viability of f(R)-gravity as an ideal fluid and its compatibility with a matter dominated phase
• The Hubble Hunter's Guide
• The significance of the largest scale CMB fluctuations in WMAP
• Age-dating Luminous Red Galaxies observed with the Southern African Large Telescope
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?
• A population of red candidate massive galaxies ~600 Myr after the Big Bang
• Measurements of the Hubble Constant: Tensions in Perspective
• Constraints on the equation of state of dark energy and the Hubble constant from stellar ages and the CMB
• Detection of non-Gaussianity in the WMAP 1-year data using spherical wavelets
• Planck 2018 results. VII. Isotropy and Statistics of the CMB
• Is the low-l microwave background cosmic?
• The $H_0$ Olympics: A fair ranking of proposed models
• Cosmology Intertwined III: $f{\sigma }_8$ and $S_8$
• Two Remarkably Luminous Galaxy Candidates at $z\approx 10-12$ Revealed by JWST
• Planck 2015 results. XVI. Isotropy and statistics of the CMB
• On the Hubble constant tension in the SNe Ia Pantheon sample
• H0LiCOW - IX. Cosmographic analysis of the doubly imaged quasar SDSS 1206+4332 and a new measurement of the Hubble constant
• The Megamaser Cosmology Project. XIII. Combined Hubble constant constraints
• Seven hints that early-time new physics alone is not sufficient to solve the Hubble tension
• CMB Anomalies after Planck
• Early results from GLASS-JWST. III: Galaxy candidates at z$\sim$9-15
• Hemispherical power asymmetry in the three-year Wilkinson Microwave Anisotropy Probe sky maps
• Setting the Stage for Cosmic Chronometers. II. Impact of Stellar Population Synthesis Models Systematics and Full Covariance Matrix
• Observational Constraints on Dark Energy and Cosmic Curvature
• Dark Energy: the equation of state description versus scalar-tensor or modified gravity
• Microwave Emission at High Galactic Latitudes
• On the evolution of the Hubble constant with the SNe Ia Pantheon Sample and Baryon Acoustic Oscillations: a feasibility study for GRB-cosmology in 2030
• Toward a Better Understanding of Cosmic Chronometers: A new measurement of H(z) at z~0.7
• Collaborative Nested Sampling: Big Data vs. complex physical models
• Evidence for anisotropy of cosmic acceleration
• Cosmic Microwave Background Quadrupole and Ellipsoidal Universe
• Arbitrating the $S_8$ discrepancy with growth rate measurements from Redshift-Space Distortions
• Probing the anisotropic local universe and beyond with SNe Ia data
• Probing cosmic isotropy with a new X-ray galaxy cluster sample through the $L_{\text{X}}-T$ scaling relation
• Ellipsoidal Universe Can Solve The CMB Quadrupole Problem
• The non-Gaussian Cold Spot in WMAP: significance, morphology and foreground contribution
• Running Hubble Tension and a H0 Diagnostic
• Anisotropically Inflating Universes
• Anisotropic Cosmological Constant and the CMB Quadrupole Anomaly
• Observational Challenges for the Standard FLRW Model
• Observational evidence for cosmological coupling of black holes and its implications for an astrophysical source of dark energy
• Constraints on a Bianchi type I spacetime extension of the standard $\Lambda$CDM model
• Implications for the Hubble tension from the ages of the oldest astrophysical objects
• Hints of FLRW Breakdown from Supernovae
• Cosmological parameter analyses using transversal BAO data
• On Larger $H_0$ Values in the CMB Dipole Direction
• Shear dynamics in Bianchi I cosmologies with R^n-gravity
• Large-scale alignments from WMAP and Planck
• Evidence of a decreasing trend for the Hubble constant
• High-Redshift Galaxies from Early JWST Observations: Constraints on Dark Energy Models
• Imperfect fluid description of modified gravities
• $f(R)$ gravity in the Jordan Frame as a Paradigm for the Hubble Tension
• BAO angular scale at z_eff = 0.11 with the SDSS blue galaxies
• Age of High Redshift Objects - a Litmus Test for the Dark Energy Models
• Cosmological parameter inference with Bayesian statistics
• Testing spatial curvature and anisotropic expansion on top of the $\Lambda$CDM model
• Anisotropy of the Universe via the Pantheon supernovae sample revisited
• Current Constraints on Anisotropic and Isotropic Dark Energy Models
• Cosmological constraints from a joint analysis of cosmic growth and expansion
• Anisotropy in the all-sky distribution of galaxy morphological types
• Constraining the dark energy models using Baryon Acoustic Oscillations: An approach independent of $H_0\cdot r_d$
• Do supernovae indicate an accelerating universe?
• Constraining An Exact Brans-Dicke gravity theory with Recent Observations
• Directional dependence of LCDM cosmological parameters
• Exact cosmological solution of a Scalar-Tensor Gravity theory compatible with the $\Lambda CDM$ model
• Anisotropic massive Brans-Dicke gravity extension of the standard $\Lambda$CDM model
• Formalizing Anisotropic Inflation in Modified Gravity
• Direction dependence of cosmological parameters due to cosmic hemispherical asymmetry
• Constraining f(R) models with cosmic chronometers and the HII galaxy Hubble diagram
• Equivalence between Scalar-Tensor theories and $f(R)$-gravity: From the action to Cosmological Perturbations

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