Ricci cosmology in light of astronomical data

Abstract

Recently, a new cosmological framework, dubbed Ricci Cosmology, has been proposed. Such a framework has emerged from the study of relativistic dynamics of fluids out of equilibrium in a curved background and is characterised by the presence of deviations from the equilibrium pressure in the energy-momentum tensor which are due to linear terms in the Ricci scalar and the Ricci tensor. The coefficients in front of such terms are called the second order transport coefficients and they parametrise the fluid response to the pressure terms arising from the spacetime curvature. Under the preliminary assumption that the second order transport coefficients are constant, we find the simplest solution of Ricci cosmology in which the presence of pressure terms causes a departure from the perfect fluid redshift scaling for matter components filling the Universe. In order to test the viability of this solution, we make four different ansätze on the transport coefficients, giving rise to four different cases of our model. On the physical ground of the second law of thermodynamics for fluids with non-equilibrium pressure, we find some theoretical bounds (priors) on the parameters of the models. Our main concern is then the check of each of the case against the standard set of cosmological data in order to obtain the observational bounds on the second order transport coefficients. We find those bounds also realising that Ricci cosmology model is compatible with $\Lambda$CDM cosmology for all the ansätze.

14 pages, 5 tables, no figures, Revtex 4-1, an improved version

References in corpus (18)

• Dynamics of dark energy
• In the Realm of the Hubble tension $-$ a Review of Solutions
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Beyond the Cosmological Standard Model
• Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z$\sim$2
• Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey
• The trouble with $H_0$
• Viscous Cosmology for Early- and Late-Time Universe
• Does Bulk Viscosity Create a Viable Unified Dark Matter Model?
• A rapid transition of $G_{\mathrm{eff}}$ at $z_t\simeq 0.01$ as a solution of the Hubble and growth tensions
• Beyond BAO: improving cosmological constraints from BOSS with measurement of the void-galaxy cross-correlation
• Can a matter-dominated model with constant bulk viscosity drive the accelerated expansion of the universe?
• Cosmic viscosity as a remedy for tension between PLANCK and LSS data
• Dissipative or Conservative cosmology with dark energy ?
• Dark Energy Coupled with Dark Matter in Viscous Fluid Cosmology
• Measuring the 2D Baryon Acoustic Oscillation signal of galaxies in WiggleZ: Cosmological constraints
• Constraining a matter-dominated cosmological model with bulk viscosity proportional to the Hubble parameter
• Scalar field unification of interacting viscous dark fluid from a geometrical scalar-tensor theory of gravity

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