Asymptotic and exact solutions of perfect-fluid scalar-tensor cosmologies

Navarro, A.; Serna, A.; Alimi, Jean‐Michel

doi:10.1103/physrevd.59.124015

Cited by 14 publications

(16 citation statements)

References 49 publications

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“…Exact solutions with κ = 0 have been found to Eqs. ( 134) and (135) in [94,1004,108,942], and vacuum and radiation dominated solutions for arbitrary spatial curvature have been found in [95,899,111]. Some of the methods used in these papers are extended to anisotropic cosmologies in [898], and the asymptotics of FLRW cosmologies in scalar-tensor theories have been studied in [112,1125].…”

Section: General Scalar-tensor Theoriesmentioning

confidence: 99%

Modified Gravity and Cosmology

Clifton,

Ferreira,

Padilla

et al. 2011

Preprint

501

847

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In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f (R), general higher-order theories, Hořava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Parameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.

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Section: General Scalar-tensor Theoriesmentioning

confidence: 99%

Modified Gravity and Cosmology

Clifton,

Ferreira,

Padilla

et al. 2011

Preprint

501

847

View full text Add to dashboard Cite

show abstract

“…This has indeed attracted a lot of interest recently and such cosmological models have been studied and possibly confronted with observations like CMB anisotropies, or the growth of energy density perturbations (see for instance [25,26,27,28,29,30,31,32,33,34,35]). However, we emphasize once more that the central point of view adopted here, in analogy with Starobinsky [14], is to constrain the model with the experimental knowledge of the Hubble diagram up to z ∼ (1 − 2).…”

Section: Introductionmentioning

confidence: 99%

Scalar-tensor gravity in an accelerating universe

2001

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We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of the Lagrangian, and we stress that apparent singularities are sometimes artifacts of a pathological choice of variables. Adopting a phenomenological viewpoint, i.e., from the observations back to the theory, we show that the knowledge of the luminosity distance as a function of redshift up to z ∼ (1 − 2), which is expected in the near future, severely constrains the viable subclasses of scalar-tensor theories. This is due to the requirement of positive energy for both the graviton and the scalar partner. Assuming a particular form for the Hubble diagram, consistent with present experimental data, we reconstruct the microscopic Lagrangian for various scalar-tensor models, and find that the most natural ones are obtained if the universe is (marginally) closed.

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“…In the so-called Jordan frame and Brans-Dicke like parametrization STG form a collection of theories which contain two functional degrees of freedom, a coupling function ω(Ψ) and a scalar potential V (Ψ). As has been discussed by many authors previously [7,8,9,10,11,12,13,14,15,16], for a range of choices of ω and V the cosmological evolution of dust and potential dominated STG models naturally converges close to the one expected from GR. On the other hand, cosmological observations and data from the local weak field tests permit to suppose that only these STG models are viable which involve this property.…”

Section: Introductionmentioning

confidence: 52%

“…Note that a necessary condition for crossing the so-called phantom divide, w eff = −1, is vanishing of the second term in Eq. (14). Depending on the model, exponential solutions may cross the phantom divide line at most twice before approaching w eff = −1 from either above or below.…”

Section: Potential Dominated Regimementioning

confidence: 99%

Scalar-tensor cosmological models converging to general relativity: potential dominated and matter dominated cases

Saal

Järv

Kuusk

2012

J. Phys.: Conf. Ser.

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We consider Friedmann-Lemaître-Robertson-Walker flat cosmological models in the framework of general Jordan frame scalar-tensor theories of gravity in two different cases: in the dust matter dominated era and in the potential dominated era. Motivated by the local weak field constraints and by cosmological observations, we develop and use an approximation scheme for the regime close to the so-called limit of general relativity. The ensuing nonlinear approximate equations for the scalar field and the Hubble parameter can be solved analytically in cosmological time in both cases. We find criteria for the functions ω and V characterizing a scalar-tensor theory, to determine whether the theory does or does not possess solutions converging to general relativity asymptotically in time. The converging solutions can be subsumed under two principal classes: exponential or polynomial convergence, and damped oscillations around general relativity. The classes of scalar-tensor theories of gravity which contain these types of solutions and satisfy observational constraints, are candidates to explain possible deviations from the standard ΛCDM model. Finally, the effective equation of state parameter w eff is used to illustrate possible asymptotic cosmological dynamics.

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Asymptotic and exact solutions of perfect-fluid scalar-tensor cosmologies

Cited by 14 publications

References 49 publications

Modified Gravity and Cosmology

Modified Gravity and Cosmology

Scalar-tensor gravity in an accelerating universe

Scalar-tensor cosmological models converging to general relativity: potential dominated and matter dominated cases

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