相关论文: Pre-inflationary dynamics in loop quantum cosmolog…
We consider initial conditions for inflation in non-minimal kinetic coupling theory. If inflation is driven solely by kinetic term with no potential, the resulting number of e-folds depends only upon initial velocity of the scalar field…
Qualitative dynamics of three different loop quantizations of spatially flat isotropic and homogeneous models is studied using effective spacetime description of the underlying quantum geometry. These include the standard loop quantum…
We started the evolution of a flat universe from a nonsingular state called prematter which is governed by an inflationary equation of state $P=(\gamma_{p}-1)\rho$ where $\gamma_{p}$ represents the initial vacuum dominance of the universe.…
We discuss a novel scenario for early cosmology, when the inflationary quasi-de Sitter phase dynamically originates from the initial quantum state represented by the microcanonical density matrix. This genuine quantum effect occurs as a…
We study the quantum evolution of the early universe, its semi-classical analogue together with inflationary regime, in view of a generalized modified theory of gravity. The action is built by supplementing the non-minimally coupled…
The slow-roll approximation is an analytical approach to study dynamical properties of the inflationary universe. In this article, systematic construction of the slow-roll expansion for effective loop quantum cosmology is presented. The…
This article is based on the Planckon densely piled vacuum model and the principle of cosmology. With the Planck era as initial conditions and including the early inflation, we have solved the Einstein-Friedmann equations to describe the…
Until recently our knowledge of the primordial curvature perturbation was relatively modest. Ever since COBE delivered its map of data we know the scalar spectrum of primordial perturbations is approximately flat, with the power being only…
We consider that the pre-inflation era is radiation-dominated, transiting smoothly to the inflationary era. We work out in detail the dynamics of inflaton fluctuations across the phase transition and the proper choices of initial vacuum…
The theory of reheating of the Universe after inflation is developed. The transition from inflation to the hot Universe turns out to be strongly model-dependent and typically consists of several stages. Immediately after inflation the field…
In the first part of this paper, we outline the construction of an inflationary cosmology in the framework where inflation is described by a universally evolving scalar field, with the Lagrangian ${\cal L}_\phi=-{1/2}(\partial\phi)^2…
We show that the semiclassical approximation to the Wheeler-DeWitt equation for the minisuperspace of a minimally coupled scalar field in the spatially flat de Sitter Universe prompts the existence of an initial power-law evolution driven…
In this work, we investigate the post-inflationary dynamics of a simple single-field model with a renormalizable inflaton potential featuring a near-inflection point at a field value $\phi_0$. Due to the concave shape of the scalar…
Inflationary cosmology with a preceding nonsingular bounce can lead to changes on the primordial density fluctuations. One significant prediction is that the amplitude of the power spectrum may undergo a jump at a critical scale. In this…
In this paper we study possible observational consequences of the bouncing cosmology. We consider a model where a phase of inflation is preceded by a cosmic bounce. While we consider in this paper only that the bounce is due to loop quantum…
In this paper the scalar-tensor theory of gravity is assumed to describe the evolution of the universe and the gravitational scalar $\phi$ is ascribed to play the role of inflaton. The theory is characterized by the specified coupling…
We propose a mechanism for generating an inflationary phase in the early universe without resorting to any type of scalar field(s). Instead, this accelerated expansion is driven by a dynamical "cosmological constant" in the framework of…
Inflation is a highly favoured theory for the early Universe. It is compatible with current observations of the cosmic microwave background and large scale structure and is a driver in the quest to detect primordial gravitational waves. It…
The inflationary dynamics and preheating in a model with a non-minimally coupled inflaton field in the metric and Palatini formalisms are studied in this paper. We find that in both formalisms, irrespective of the initial conditions, our…
In the landscape perspective, our Universe begins with a quantum tunneling from an eternally-inflating parent vacuum, followed by a period of slow-roll inflation. We investigate the tunneling process and calculate the probability…