Related papers: Cosmic Initial Conditions for a Habitable Universe
Quantum origin of the early inflationary Universe from the no-boundary and tunnelling quantum states is considered in the one-loop approximation of quantum cosmology. A universal effective action algorithm for the distribution function of…
The hypothesis that the Universe underwent a period of exponential expansion at very early times has become the most popular theory of the early Universe. Not only does it solve some of the problems of standard big bang cosmology, but it…
We investigate the quantum cosmological tunneling scenario for inflationary models. Within a path-integral approach, we derive the corresponding tunneling probability distribution. A sharp peak in this distribution can be interpreted as the…
As a nonbaryonic explanation of massive compact halo objects, a phenomenological model is presented which predicts formation of primordial black holes at a desired mass scale. The required feature of initial density fluctuation is realized…
The inflationary scenario has become the paradigm of early universe cosmology, and - in conjuction with ideas from superstring theory - has led to speculations about an "inflationary multiverse". From a point of view of phenomenology, the…
We investigate whether inflation requires finely tuned initial conditions in order to explain the degree of flatness and homogeneity observed in the Universe. We achieve this by using the Eisenhart lift, which can be used to write any…
Recent developments in cosmology suggest that much of the universe is in a state of explosive, accelerated expansion, called inflation. We live in a "bubble" where inflation has ended, and other bubbles with diverse properties are…
In a multiverse context, determining the probability of being in our particular universe depends on estimating its overall habitability compared to other universes with different values of the fundamental constants. One of the most…
Early universe equations of state including realistic interactions between constituents are built up. Under certain reasonable assumptions, these equations are able to generate an inflationary regime prior to the nucleosynthesis period. The…
Motivated by the possibility that different versions of the laws of physics could be realized within other universes, this paper delineates the galactic parameters that allow for habitable planets and revisits constraints on the amplitude…
We propose a cosmological scenario which describes the evolution history of the universe based on the particle creation and holographic equipartition. The model attempts to solve the inflation of the early universe and the accelerated…
We discuss various models of inflationary universe with $\Omega \not = 1$. A homogeneous universe with $\Omega > 1$ may appear due to creation of the universe "from nothing" in the theories where the effective potential becomes very steep…
Cosmological inflation, if it occurred, radically alters the picture of the `big bang', which would merely point to reheating at the end of inflation. Moreover, this reheating may be only local, so that inflation continues elsewhere and…
Current observational data is consistent with the universe being slightly closed. We investigate families of singular and non-singular closed instantons that could describe the beginning of a closed inflationary universe. We calculate the…
The probability for quantum creation of an inflationary universe with a pair of black holes is computed in a modified gravitational theory. Considering a gravitational action which includes a cosmological constant ($\Lambda$) in addition to…
We apply the principles of quantum mechanics and quantum cosmology to predict probabilities for our local observations of a universe undergoing false vacuum eternal inflation. At a sufficiently fine-grained level, histories of the universe…
We consider a universe with a bulk viscous cosmic fluid, in a flat Friedmann-Lemaitre-Robertson-Walker geometry. We derive the conditions for the existence of inflation, and those which at the same time prevent the occurrence of…
We investigate higher dimensional cosmological models in the semiclassical approximation with Hartle-Hawking Boundary conditions, assuming a gravitational action which is described by the scalar curvature with a cosmological constant. In…
A new model of the observed universe, using solutions to the full Einstein equations, is developed from the hypothesis that our observable universe is an underdense bubble, with an internally inhomogeneous fractal bubble distribution of…
We review here some recent results that show that inflationary cosmological models must contain initial singularities. We also present a new singularity theorem. The question of the initial singularity re-emerges in inflationary cosmology…