相关论文: A Note in Cosmology and Loop Quantum Gravity

This chapter provides a review of the frameworks developed for cosmological perturbation theory in loop quantum cosmology, and applications to various models of the early universe including inflation, ekpyrosis and the matter bounce, with…

Loop quantum cosmology is a symmetry-reduced application of loop quantum gravity. The theory predicts a bounce for the universe at the Planck scale and resolves the singularity of standard cosmology. The dynamics is also governed by an…

We propose a method to extract predictions from quantum cosmology for inflation that can be confronted with observations. Employing the tunneling boundary condition in quantum geometrodynamics, we derive a probability distribution for the…

In these lectures I focus on early universe models which can explain the currently observed structure on large scales. I begin with a survey of inflationary cosmology, the current paradigm for understanding the origin of the universe as we…

Inflationary cosmology explains the homogeneity and large-scale structure of the universe through a brief epoch of accelerated expansion following the Big Bang. Cyclic cosmologies, in contrast, describe a universe undergoing successive…

The standard model of cosmology assumes a homogeneous and isotropic universe that undergoes a period of exponential expansion very early on, named inflation. This stretches quantum fluctuations from the onset of inflation to cosmological…

Using techniques from loop quantum gravity, the standard theory of cosmological perturbations was recently generalized to encompass the Planck era. We now apply this framework to explore pre-inflationary dynamics. The framework enables us…

Inflation plays a central role in our current understanding of the universe. According to the standard viewpoint, the homogeneous and isotropic mode of the inflaton field drove an early phase of nearly exponential expansion of the universe,…

The usual description of inflationary fluctuations uses the framework of quantum field theory (QFT) in curved spacetime, in which quantum fluctuations are superimposed on a classical background spacetime. Even for large fluctuations, such…

We propose a scenario of the beginning of inflation in which the non-vacuum value of the scalar field that drives inflation develops dynamically due to the non-minimal coupling to gravity. In this scenario, inflation emerges as an…

Since the standard inflationary paradigm is based on quantum field theory on classical space-times, it excludes the Planck era. Using techniques from loop quantum gravity, the paradigm is extended to a self-consistent theory from the Planck…

An introductory account is given of the modern understanding of the physics of the early Universe. Particular emphasis is placed on the paradigm of cosmological inflation, which postulates a period of accelerated expansion during the…

Inflationary cosmology has, in the last few years,received a strong dose of support from observations. The fact that the fluctuation spectrum can be extracted from the inflationary scenario through an analysis that involves quantum field…

Inflationary cosmology proposes that the early Universe undergoes accelerated expansion, driven, in simple scenarios, by a single scalar field, or inflaton. The form of the inflaton potential determines the initial spectra of density…

Dynamics of the inflaton scalar field oscillating around a minimum of the singular potentials in the expanding Universe is investigated. Asymptotic formulas are obtained describing the cosmological expansion at the late times. The problem…

Using computer simulations we study the geometry of a typical quantum universe, i.e. the geometry one might expect before a possible period of inflation. We display it using coordinates defined by means of four classical scalar fields…

After introducing the basic ingredients of Loop Quantum Cosmology, I will briefly discuss some of its phenomenological aspects. Those can give some useful insight about the full Loop Quantum Gravity theory and provide an answer to some…

The standard inflationary version of the origin of the cosmic structure as the result of the quantum fluctuations during the inflationary stage is less than fully satisfactory: how exactly does the Universe transit from a homogeneous and…

The early universe provides an opportunity for quantum gravity to connect to observation by explaining the large-scale structure of the Universe. In the group field theory (GFT) approach, a macroscopic universe is described as a GFT…

A brief review of the modern state of quantum cosmology is presented as a theory of quantum initial conditions for inflationary scenario. The no-boundary and tunneling states of the Universe are discussed as a possible source of probability…