Power spectra from an inflaton coupled to the Gauss-Bonnet term

Guo, Zong-Kuan; Schwarz, Dominik J.

doi:10.1103/physrevd.80.063523

Cited by 124 publications

(67 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gauss-Bonnet gravities, for which a non-linear function f (G) of the Gauss-Bonnet invariant is included in the action [36][37][38][39][40][41][42], are worthy of special mention. Some cosmological solutions have been explored, including the exact Λ Cold Dark Matter (ΛCDM) [43,44] and some inflationary models [45][46][47][48][49][50][51][52], as an accelerating expansion can be easily achieved. Nevertheless, the presence of non-linear Gauss-Bonnet terms in the action may introduce ghost instabilities in an empty anisotropic universe, that is, Kasner-type background, although such instabilities are absent on Friedmann-Lemaître-Robertson-Walker (FLRW) cosmologies (see [53]).…”

Section: Introductionmentioning

confidence: 99%

Inflation in Mimetic f(G) Gravity

Zhong

Sáez-Gómez

2018

Symmetry

View full text Add to dashboard Cite

Mimetic gravity is analysed in the framework of some extensions of general relativity (GR), whereby a function of the Gauss-Bonnet invariant in four dimensions is considered. By assuming the mimetic condition, the conformal degree of freedom is isolated, and a pressureless fluid naturally arises. Then, the complete set of field equations for mimetic Gauss-Bonnet gravity is established, and some inflationary models are analysed, for which the corresponding gravitational action is reconstructed. The spectral index and tensor-to-scalar ratio are obtained and compared with observational bounds from Planck and BICEP2/Keck array data. Full agreement with the above data is achieved for several versions of the mimetic Gauss-Bonnet gravity. Finally, some extensions of Gauss-Bonnet mimetic gravity are considered, and the possibility of reproducing inflation is also explored.

show abstract

Section: Introductionmentioning

confidence: 99%

Inflation in Mimetic f(G) Gravity

Zhong

Sáez-Gómez

2018

Symmetry

View full text Add to dashboard Cite

show abstract

“…When c 2 = 0 and ǫ = 1 the solutions correspond to obtained in [18][19][20] in the case of the direct choice of the constants c 1 and m.…”

Section: Power Law Solutionmentioning

confidence: 69%

Exact inflation in Einstein–Gauss–Bonnet gravity

Фомин

Chervon

2017

Gravit. Cosmol.

View full text Add to dashboard Cite

We study cosmological inflation in the Einstein gravity model, where additionally the Gauss-Bonnet term non-minimally coupled to a scalar field is included. We prove that inflationary solutions of exponential and power-law types are allowable and we found few examples of them. We also proposed the method of the exact inflationary solutions construction for a single scalar field with given scale factor and Gauss-Bonnet coupling term in the spatially flat Friedmann-Robertson-Walker Universe on the basis of connection with standard inflation and using special anzatses. With one special anzats we presented the system of equations in the form which allowed generation of exact solutions (at least in quadratures) of wide class by setting the scale factor.

show abstract

“…1, 2, 3 and 4 displayed were produced by assuming the values C 1 = −0.02, C 2 = −50, C 3 = −0.05, α = −150, C = 0.0002 and β = αC. (Observe that the use of a negative coupling constant α is not novel-see for example Guo and Schwarz [30]). For these choices it is pleasing to note from Fig.…”

Section: Physical Featuresmentioning

confidence: 99%

Exact EGB models for spherical static perfect fluids

2015

View full text Add to dashboard Cite

We obtain a new exact solution to the field equations for a 5-dimensional spherically symmetric static distribution in the Einstein-Gauss-Bonnet modified theory of gravity. By using a transformation, the study is reduced to the analysis of a single second order nonlinear differential equation. In general the condition of pressure isotropy produces a first order differential equation which is an Abel equation of the second kind. An exact solution is found. The solution is examined for physical admissibility. In particular a set of constants is found which ensures that a pressure-free hypersurface exists which defines the boundary of the distribution. Additionally the isotropic pressure and the energy density are shown to be positive within the radius of the sphere. The adiabatic sound-speed criterion is also satisfied within the fluid ensuring a subluminal sound speed. Furthermore, the weak, strong and dominant conditions hold throughout the distribution. On setting the Gauss-Bonnet coupling to zero, an exact solution for 5-dimensional perfect fluids in the standard Einstein theory is obtained. Plots of the dynamical quantities for the Gauss-Bonnet and the Einstein case reveal that the pressure is unaffected, while the energy density increases under the influence of the Gauss-Bonnet term.

show abstract

Power spectra from an inflaton coupled to the Gauss-Bonnet term

Cited by 124 publications

References 36 publications

Inflation in Mimetic f(G) Gravity

Inflation in Mimetic f(G) Gravity

Exact inflation in Einstein–Gauss–Bonnet gravity

Exact EGB models for spherical static perfect fluids

Contact Info

Product

Resources

About