REVIEW 3 cited by
Friedmann cosmology with hyperfluids
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
abstract
In metric-affine gravity, both the gravitational and matter actions depend not just on the metric, but also on the independent affine connection. Thus matter can be modeled as a hyperfluid, characterized by both the energy-momentum and hypermomentum tensors. The latter is defined as the variation of the matter action with respect to the connection and it encodes extra (micro)properties of particles. For a homogeneous and isotropic universe, it was recently shown that the generic cosmological hypermomentum possesses five degrees of freedom: one in dilation, two in shear, and two in spin part. The aim of the current work is to present the first systematic study of the implications of this perfect hyperfluid on the universe with Friedmann-Lema\^itre-Robertson-Walker metric. We adopt a simple model with non-Riemannian Einstein-Hilbert gravitational action plus arbitrary hyperfluid matter, and solve analytically the cosmological equations for single and multiple component hypermomentum contributions using different assumptions about the equation of state. It is remarkable, that in a number of cases the forms of the time evolution of the Hubble function and energy density still coincide with their general relativity counterparts, only the respective indexes $\mathrm{w}_{\mathrm{eff}}$ and $\mathrm{w}_\rho$ start to differ due to the hypermomentum corrections. The results and insights we obtained are very general and can assist in constructing interesting models to resolve the issues in standard cosmology.
Forward citations
Cited by 3 Pith papers
-
Jacobson's thermodynamic approach to classical gravity applied to non-Riemannian geometries: remarks on the simplicity of Nature
Jacobson's thermodynamic approach applied to non-Riemannian geometries selects the Einstein-Hilbert action plus a quadratic torsion term as Nature's choice when non-metricity is absent and the metric energy-momentum t...
-
Geometric formulation of $k$-essence and late-time acceleration
Integrable vectorial nonmetricity gravity is shown to be equivalent to purely kinetic quadratic k-essence, which fits late-time data as well as ΛCDM.
-
Friedmann cosmology with hyperfluids of constant equation of state
In metric-affine gravity with hyperfluids of constant equation of state, Friedmann evolution is modified by hypermomentum and depends on the constants linking hypermomentum to matter density.
Discussion (0). Sign in to comment.