Related papers: A new perspective on Gauge-flation
I study the gauge-invariant fluctuations of the metric during inflation. In the infrared sector the metric fluctuations can be represented by a coarse-grained field. We can write a Schroedinger equation for the coarse-grained metric…
A single field inflation based on a supergravity model with a shift symmetry and $U(1)$ extension of the MSSM is analyzed. We show that one of the real components of the two $U(1)$ charged scalar fields plays the role of inflaton {with} an…
In this paper, we investigate models where a scalar field driving inflation is minimally coupled with gravity and it is subjected to a scalar potential. We present several examples of coupling between the field and gravity, and we furnish…
The inflation model with non-minimal coupling scalar field in the context of the hybrid metric Palatini is studied in this paper. We derive the Einstein's field equations, the equations of motion of the scalar field. Furthermore,the…
We propose a new class of inflationary models in which the scalar field potential governing inflation is generated by the same non-perturbative gauge dynamics that may lead to supersymmetry breaking. Such models satisfy constraints from…
A Friedman cosmology is investigated based on scalar-tensor gravitation with general metric coupling and scalar potential functions. We show that for a broad class of such functions, the scalar field can be dynamically trapped using a…
In inflation with nonminimal derivative coupling there is not a conformal transformation to the Einstein frame where calculations are straightforward, and thus in order to extract inflationary observables one needs to perform a detailed and…
We show that multi-field inflationary models with negligible turning in field space during inflation can lead to an effective sourcing of adiabatic from entropic perturbations {\it after} the end of inflation. We illustrate this general…
We propose a new class of inflationary solutions to the standard cosmological problems (horizon, flatness, monopole,...), based on a modification of old inflation. These models do not require a potential which satisfies the normal…
In this paper, we discuss the constraints on the reheating temperature supposing an early post-reheating cosmological phase dominated by one or more simple scalar fields produced from inflaton decay and decoupled from matter and radiation.…
The inflationary epoch and the late time acceleration of the expansion rate of universe can be explained by assuming a gravitationally coupled scalar field. In this article, we propose a new method of finding exact solutions in the…
The early time expansion of the space-time, namely inflation, is introduced to solve some cosmological problems. $F(R)$ gravity is a simple extension of the general relativity to induce the inflationary expansion. The precise observation of…
Inflationary models with a scalar field nonminimally coupled both with the Ricci scalar and with the Gauss-Bonnet term are studied. We propose the way of generalization of inflationary scenarios with the Gauss-Bonnet term and a scalar field…
In this work we investigate a inflationary scenario generated by a large scalar field $\phi$ that non-minimally couples to a $f(R)$ modified gravity model. For a Starobinsky's like model, it is found that along a particular flat direction,…
We revisit inflation with non-canonical scalar fields by applying deformed-steepness exponential potentials. We show that the resulting scenario can lead to inflationary observables, and in particular to scalar spectral index and…
Bayesian inference techniques are used to investigate situations where an additional light scalar field is present during inflation and reheating. This includes (but is not limited to) curvaton-type models. We design a numerical pipeline…
In F-term supergravity inflation models, scalar fields other than the inflaton generically receive a Hubble induced mass, which may restore gauge symmetries during inflation and phase transitions may occur during or after inflation as the…
We propose a 3 + 1 dimensional model of gravity which results in inflation at early times, followed by radiation- and matter-dominated epochs and a subsequent acceleration at late times. Both the inflation and late time acceleration are…
We prove that in the Hartle-Hawking approach to quantum cosmology the existence of an inflationary phase is a general property of minisuperspace models given by a closed Friedmann-Robertson-Walker universe containing a massless scalar field…
We study a new class of inflation model parametrized by the Hubble radius, such that $aH\propto \exp(-k\phi^n)$. These potentials are plateau-like, and reduce to the power-law potentials in the simplest case $n=2$. We investigate the range…