Starobinsky R^2 inflation model
E732409
The Starobinsky R² inflation model is a pioneering cosmological model of the early universe in which inflation is driven by a modification of general relativity that adds a term proportional to the square of the Ricci scalar to the gravitational action.
Observed surface forms (1)
| Surface form | Occurrences |
|---|---|
| Starobinsky R + R^2 inflationary model | 1 |
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
cosmological inflation model
ⓘ
early universe model ⓘ modified gravity theory ⓘ |
| addresses |
flatness problem
ⓘ
horizon problem ⓘ monopole problem ⓘ |
| addsTerm | R^2 term in the gravitational action ⓘ |
| alsoKnownAs |
R^2 inflation
NERFINISHED
ⓘ
Starobinsky inflation NERFINISHED ⓘ |
| assumes |
Friedmann–Lemaître–Robertson–Walker metric
NERFINISHED
ⓘ
spatially homogeneous and isotropic universe ⓘ |
| basedOnTheory | general relativity ⓘ |
| belongsToClass | f(R) gravity models ⓘ |
| canBeRewrittenAs | Einstein gravity plus scalar field (Einstein frame) ⓘ |
| compatibleWith |
Planck satellite data
NERFINISHED
ⓘ
cosmic microwave background observations ⓘ |
| drives | cosmic inflation ⓘ |
| EinsteinFrameContains | scalaron field ⓘ |
| energyScale | inflation scale around 10^13 GeV (order of magnitude) ⓘ |
| framework | metric formulation of gravity ⓘ |
| hasLagrangianDensity | L ∝ R + α R^2 (in the Jordan frame) ⓘ |
| hasNumberOfEfolds | N ≈ 50–60 ⓘ |
| hasParameter | α (coefficient of the R^2 term) ⓘ |
| hasPotentialShape | plateau-like potential in the Einstein frame ⓘ |
| implies | reheating after inflation ⓘ |
| inflationDrivenBy | higher-derivative curvature term ⓘ |
| inflatonIdentifiedAs | scalaron NERFINISHED ⓘ |
| influenced |
development of f(R) gravity
ⓘ
plateau inflation models ⓘ |
| introducedBy | Alexei Starobinsky NERFINISHED ⓘ |
| introducedIn | 1980 ⓘ |
| is | one of the earliest concrete inflationary models ⓘ |
| isExampleOf | single-field slow-roll inflation ⓘ |
| leadsTo | graceful exit from inflation via R^2 term decay ⓘ |
| modifies | Einstein–Hilbert action NERFINISHED ⓘ |
| namedAfter | Alexei Starobinsky NERFINISHED ⓘ |
| notableFor | geometric origin of the inflaton degree of freedom ⓘ |
| oftenComparedWith |
Higgs inflation
ⓘ
chaotic inflation models ⓘ |
| originalPublication | A. A. Starobinsky, Physics Letters B 91 (1980) 99–102 ⓘ |
| predicts |
Gaussian primordial perturbations (to leading order)
ⓘ
nearly scale-invariant spectrum of scalar perturbations ⓘ quasi–de Sitter expansion in the early universe ⓘ small tensor-to-scalar ratio ⓘ |
| predictsScalarSpectralIndex | n_s ≈ 1 − 2/N ⓘ |
| predictsTensorToScalarRatio | r ≈ 0.003 (for N ≈ 60 e-folds) ⓘ |
| requires | positive coefficient of the R^2 term for stability ⓘ |
| usesQuantity | Ricci scalar ⓘ |
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Starobinsky R + R^2 inflationary model