Related papers: Anisotropic inflation with coupled $\boldsymbol{p}…
We examine whether an extended scenario of a two-scalar-field model, in which a mixed kinetic term of canonical and phantom scalar fields is involved, admits the Bianchi type I metric, which is homogeneous but anisotropic spacetime, as its…
Although natural inflation is a theoretically well-motivated model for cosmic inflation, it is in tension with recent Planck cosmic microwave background anisotropy measurements. We present a way to alleviate this tension by considering a…
Vacuum multidimensional cosmological models with internal spaces being compact $n$-dimensional Lie group manifolds are considered. Products of 3-spheres and $SU(3)$ manifold (a novelty in cosmology) are studied. It turns out that the…
In spirit of the recently proposed four-parameter generalized entropy of apparent horizon, we investigate inflationary cosmology where the matter field inside of the horizon is dominated by a scalar field with a power law potential (i.e.,…
We investigate the dynamical properties of a class of spatially homogeneous and isotropic cosmological models containing a barotropic perfect fluid and multiple scalar fields with independent exponential potentials. We show that the…
We investigate the stability of cosmological scaling solutions describing a barotropic fluid with $p=(\gamma-1)\rho$ and a non-interacting scalar field $\phi$ with an exponential potential $V(\phi)=V_0\e^{-\kappa\phi}$. We study homogeneous…
We explore a model of inflation where the inflaton mass-squared is generated at a high scale by gravity-mediated soft supersymmetry breaking, and runs at lower scales to the small value required for slow-roll inflation. The running is…
The dynamics of the tilted axisymmetric Bianchi IX cosmological models are explored allowing energy flux in the source fluid. The Einstein equations and the continuity equation are presented treating the equation of state $w$ and the tilt…
The inflationary scenario, which states that the early universe underwent a brief but dramatic period of accelerated spatial expansion, has become the current paradigm of early universe cosmology. Although inflationary cosmology has its…
Scattering amplitudes at weak coupling are highly constrained by Lorentz invariance, locality and unitarity, and depend on model details only through coupling constants and particle content. In this paper, we develop an understanding of…
A primordial inflationary phase allows one to erase any possible anisotropic expansion thanks to the cosmic no-hair theorem. If there is no global anisotropic stress, then the anisotropic expansion rate tends to decrease. What are the…
Recent observations of large-scale statistical isotropy violations have prompted the adoption of anisotropic cosmological models that account for inherent directional curvature. Studies of these anisotropic spacetimes have shown how they…
Understanding mechanisms capable of altering the vacuum energy is currently of interest in field theories and cosmology. We consider an interacting scalar field and show that the vacuum energy naturally takes any value between its maximum…
We investigate the dynamics of the recently proposed model of assisted inflation. In this model an arbitrary number of scalar fields with exponential potentials evolve towards an inflationary scaling solution, even if each of the individual…
The evolution of two slow--rolling scalar fields with potentials of the form $V=V_0 \phi^{-\alpha}\exp(-\beta \phi^m)$ is studied. Considering different values of the parameters $\alpha$, $\beta$ and $m$, we derive several new inflationary…
Soft limits of $N$-point correlation functions, in which one wavenumber is much smaller than the others, play a special role in constraining the physics of inflation. Anisotropic sources such as a vector field during inflation generate…
We study inflation with multiple vector fields. In the presence of non-trivial couplings between the inflaton and the vector fields, it turns out that no-hair conjecture does not hold and vector-hair appears. In the case of uniform…
Inflationary scenarios based on simple non-minimal coupling and its generalizations are studied. Generalizing the form of non-minimal coupling to "K(phi)R" with an arbitrary function K(phi), we show that the flat potential still is…
We calculate the anisotropic signal associated with the coupling of a three-form with an Abelian vector gauge field. In the simplest examples of three-form inflation the amplification of the vector fluctuations is exponential; this makes it…
In the framework of geometrothermodynamics, we explore how to construct an inflationary cosmic fluid without requiring inflaton fields. To do so, we employ standard radiation and matter as barotropic background, speculating on the existence…