Inflationary perturbations in Palatini generalized gravity

Journal Article · Tue Feb 15 00:00:00 EST 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.044018· OSTI ID:21504986

Tamanini, Nicola; Contaldi, Carlo R ^[1]

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1. Theoretical Physics, Blackett Laboratory, Imperial College, London, SW7 2BZ (United Kingdom)

We examine the generation of primordial perturbations during an inflationary epoch in generalized theories of gravity when the equations of motion are derived using the Palatini variational principle. Both f(R) and scalar-tensor theories are considered, and we compare our results with those obtained under the conventional metric formalism. Nonlinear generalizations of the action lead to different theories under the two variational choices, and we obtain distinct results for scalar and tensor spectral indices and their ratio. We find the following general result: Inflation driven solely by f(R) modifications does not result in suitable curvature perturbations, while scalar-tensor theories generate nearly scalar invariant curvature perturbations but no tensor modes.

• OSTI ID: 21504986
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 4; Other Information: DOI: 10.1103/PhysRevD.83.044018; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COMPARATIVE EVALUATIONS
DISTURBANCES
EQUATIONS OF MOTION
GENERAL RELATIVITY THEORY
GRAVITATION
METRICS
MODIFICATIONS
NONLINEAR PROBLEMS
PERTURBATION THEORY
VARIATIONAL METHODS
CALCULATION METHODS
DIFFERENTIAL EQUATIONS
EQUATIONS
EVALUATION
FIELD THEORIES
PARTIAL DIFFERENTIAL EQUATIONS
RELATIVITY THEORY