Related papers: Supergravity Contributions to Inflation in models …
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 cosmological particle production associated with inflationary fluctuations by comparing gravitational and geometric mechanisms, within a non-minimal Yukawa-like coupling between a inflaton and spacetime curvature. We show under…
We study various inflation models in the Jordan frame supergravity with a logarithmic Kahler potential. We find that, in a class of inflation models containing an additional singlet in the superpotential, three types of inflation can be…
This thesis investigates a toy model for inflation in a class of modified theories of gravity in the metric formalism. Instead of the standard procedure -- assuming a non-linear Lagrangian $f(R)$ in the Jordan frame -- we start from a…
We reconsider an inflationary model that inflaton field is non-minimally coupled to gravity. We study parameter space of the model up to the second ( and in some cases third ) order of the slow-roll parameters. We calculate inflation…
We consider the inflationary scenario with non-minimal coupling in 4D Jordan frame supergravity. We find that there occurs a tachyonic instability along the direction of the accompanying non-inflaton field in generic Jordan frame…
In this paper we study some classes of $\alpha$-attractors models in the Jordan frame and we find the corresponding $F(R)$ gravity theory. We study analytically the problem at leading order and we investigate whether the attractor picture…
In this work we shall study a new class of attractor models which we shall call generalized $R^p$-attractor models. This class of models is based on a generalization of the Einstein frame potential of $R^p$ $f(R)$ gravity models in the…
We propose a large class of supergravity models in terms of a single chiral matter superfield, leading to (almost) arbitrary single-field inflationary scalar potentials similar to the F-term in rigid supersymmetry. Those scalar potentials…
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…
Inflation based on scalar fields which are non-minimally coupled to gravity has been proposed as a way to unify inflation with weak-scale physics, with the inflaton being identified with the Higgs boson or other weak-scale scalar article.…
The FRW model with non-minimally coupled massive scalar field has been investigated in LQC framework. Considered form of the potential and coupling allows applications to Higgs driven inflation. Out of two frames used in the literature to…
The generic embedding of the $R+R^2$ higher curvature theory into old-minimal supergravity leads to models with rich vacuum structure in addition to its well-known inflationary properties. When the model enjoys an exact R-symmetry, there is…
We examine the potential strong coupling problem at early times in a bouncing cosmological model with "strong gravity in the past" (Jordan frame), which is conformally related to inflation (Einstein frame). From naive dimensional analysis…
Supersymmetric versions of induced-gravity inflation are formulated within Supergravity (SUGRA) employing two gauge singlet chiral superfields. The proposed superpotential is uniquely determined by applying a continuous R and a discrete Z_n…
In this review, we discuss inflation models based on supergravity. After explaining the difficulties in realizing inflation in the context of supergravity, we show how to evade such difficulties. Depending on types of inflation, we give…
Supergravity is a well-motivated theory beyond the standard model of particle physics, and a suitable arena to study high-energy physics at the early universe including inflation, whose observational evidences are growing more and more.…
Most of the inflation models end up with non-vanishing vacuum expectation values of the inflaton fields \phi in the true vacuum, which induce, in general, nonvanishing auxiliary field G_\phi for the inflaton potential in supergravity. We…
We consider a subclass of Horndeski theories for studying cosmic inflation. In particular, we investigate models of inflation in which the derivative self-interaction of the scalar field and the non-minimal derivative coupling to gravity…
We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify the…