Related papers: Kaluza-Klein Higher Derivative Induced Gravity
In the context of (4+d)-dimensional general relativity, we propose an inflationary scenario wherein 3 spatial dimensions grow large, while d extra dimensions remain small. Our model requires that a self-interacting d-form acquire a vacuum…
We derive the scalar potential in four spacetime dimensions from an eight-dimensional $(R+\gamma R^4-2\Lambda-F_4^2)$ gravity model in the presence of the 4-form $F_4$, with the (modified gravity) coupling constant $\gamma$ and the…
In the present paper we consider anisotropic cosmological vacuum solutions in (4+1) dimensional general quadratic gravity. In particular, we present a solution with 3 equal and 1 different Hubble parameters, and study its stability. We show…
In this paper we investigate a model of an inflationary universe in Kaluza-Klein theory, which is a four-dimensional de Sitter space plus a one-dimensional compactified internal space. We find that the energy scale for inflation can be…
We study extended theories of gravity where nonminimal derivative couplings of the form $R^{kl}\phi_{, k}\phi_{, l}$ are present in the Lagrangian. We show how and why the other couplings of similar structure may be ruled out and then…
We consider the compactification of (d+n)-dimensional pure gravity and of superstring/M-theory on an n-dimensional internal space to a d-dimensional FLRW cosmology, with spatial curvature k=-1,0,+1, in Einstein conformal frame. The internal…
We generalise Starobinsky's model of inflation to space-times with $D>4$ dimensions, where $D-4$ dimensions are compactified on a suitable manifold. The $D$-dimensional action features Einstein-Hilbert gravity, a higher-order curvature…
One common approach for cosmic inflation consists in couple Einstein's gravity with a scalar field, often referred to inflaton field. In order to derive analytic simple scenarios, we usually work in the {\it slow-roll} regime. In such an…
During inflation, higher derivative terms in the gravitational action may play a significant role. Building on new stable formulations of four-derivative scalar-tensor theories, we study the impact of these corrections in the case where the…
We explore an effective 4D cosmological model for the universe where the variable cosmological constant governs its evolution and the pressure remains negative along all the expansion. This model is introduced from a 5D vacuum state where…
We study two $(4+n)$-dimensional branes embedded in $(5+n)$-dimensional spacetime. Using the gradient expansion approximation, we find that the effective theory is described by $(4+n)$-dimensional scalar-tensor gravity with a specific…
Very few explicit inflationary scenarios are known to generate a large bispectrum of orthogonal shape. Dirac-Born-Infeld Galileon inflation, in which an induced gravity term is added to the DBI action, is one such model. We formulate it in…
The manuscript studies a 3+N+1-dimensional space in which the N extra dimensions are dynamically compact. The 3 large dimensions, behaving as the spacial part of the FRW metric, possess a different scale factor in comparison with the N…
Dark matter and cosmic inflation represent two of the major puzzles in cosmology. They are typically addressed by introducing separate fields with independent dynamics. On the other hand, extra dimensions might play an important role for…
We show that the combination of cubic invariants defining five-dimensional quasitopological gravity, when written in four dimensions, reduce to the version of four-dimensional Einsteinian gravity recently proposed by Arciniega, Edelstein &…
One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the ultra-violet regime can admit non-singular…
We consider gravity theories in $4+N$ dimensions which are governed by the Lagrangian written as an extended Gauss-Bonnet density. We can find a naturally generalized Einstein gravity where the maximal symmetric compactification leads to…
We propose a natural scenario for the cosmological inflation with the non-minimal coupling term invoking compact hyperbolic extra dimensions. Thanks to the unique mathematical properties of compact hyperbolic space, the large volume of…
In $D$-dimensional dilaton gravitational model with the central charge deficit the generalized Friedmann-type cosmological solutions (spatially homogeneous and isotropic) are obtained and classified.
We discuss a semiclassical treatment to inflationary models from Kaluza-Klein theory without the cylinder condition. We conclude that the evolution of the early universe could be described by a geodesic trayectory of a cosmological 5D…