REVIEW 7 cited by
Cosmological perturbations in the Palatini formulation of modified gravity
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
Signed reviews
read the original abstract
Cosmology in extended theories of gravity is considered assuming the Palatini variational principle, for which the metric and connection are independent variables. The field equations are derived to linear order in perturbations about the homogeneous and isotropic but possibly spatially curved background. The results are presented in a unified form applicable to a broad class of gravity theories allowing arbitrary scalar-tensor couplings and nonlinear dependence on the Ricci scalar in the gravitational action. The gauge-ready formalism exploited here makes it possible to obtain the equations immediately in any of the commonly used gauges. Of the three type of perturbations, the main attention is on the scalar modes responsible for the cosmic large-scale structure. Evolution equations are derived for perturbations in a late universe filled with cold dark matter and accelerated by curvature corrections. Such corrections are found to induce effective pressure gradients which are problematical in the formation of large-scale structure. This is demonstrated by analytic solutions in a particular case. A physical equivalence between scalar-tensor theories in metric and in Palatini formalisms is pointed out.
Forward citations
Cited by 7 Pith papers
-
Quasi-pole inflation in metric-affine gravity
Non-minimal coupling of the inflaton to the Holst invariant in metric-affine gravity induces quasi-pole kinetics that generate an exponential plateau potential and Starobinsky-equivalent predictions regardless of the ...
-
Inflation in non-local hybrid metric-Palatini gravity
Non-local hybrid metric-Palatini gravity generically contains ghosts, but a degenerate subclass with metric f(R) gravity plus Palatini non-local terms is ghost-free and can drive slow-roll inflation resembling Starobi...
-
Cosmological phase space of generalized hybrid metric-Palatini theories of gravity
A dynamical-systems analysis of f(R,ℛ) hybrid metric-Palatini gravity shows no global attractors in the cosmological phase space and only two classes of fixed-point scale factors, one of which predicts a jerk paramete...
-
Natural Metric-Affine Inflation: Reloaded
Combining periodic non-minimal couplings to the Nieh-Yan term and Ricci scalar in metric-affine gravity makes natural inflation viable for sub-Planckian periodicity scales.
-
$\tilde\xi$-attractors in metric-affine gravity
A new class of metric-affine inflationary models, the ξ-tilde-attractors, reproduces Starobinsky inflation as a universal attractor in two strong-coupling limits.
-
Palatini Linear Attractors Are Back in ACTion
In Palatini gravity, quadratic potentials with a linear non-minimal coupling or linear potentials with an αR^2 term can match the ACT spectral index while keeping the tensor-to-scalar ratio below current limits.
-
Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
Modified gravity theories supply viable mathematical frameworks for inflation, bounces, and dark energy eras that match observational data.
Discussion (0). Continue with ORCID to comment.