Inflationary universe: A possible solution to the horizon and flatness problems
Abstract
The standard model of hot bigbang cosmology requires initial conditions which are problematic in two ways: (1) The early universe is assumed to be highly homogeneous, in spite of the fact that separated regions were causally disconnected (horizon problem); and (2) the initial value of the Hubble constant must be fine tuned to extraordinary accuracy to produce a universe as flat (i.e., near critical mass density) as the one we see today (flatness problem). These problems would disappear if, in its early history, the universe supercooled to temperatures 28 or more orders of magnitude below the critical temperature for some phase transition. A huge expansion factor would then result from a period of exponential growth, and the entropy of the universe would be multiplied by a huge factor when the latent heat is released. Such a scenario is completely natural in the context of grand unified models of elementaryparticle interactions. In such models, the supercooling is also relevant to the problem of monopole suppression. Unfortunately, the scenario seems to lead to some unacceptable consequences, so modifications must be sought.
 Authors:
 Publication Date:
 Research Org.:
 Stanford Linear Accelerator Center, Stanford University, Stanford, California 94305
 OSTI Identifier:
 6981740
 DOE Contract Number:
 DEAC0376SF00515
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Phys. Rev., D; (United States); Journal Volume: 23:2
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGICAL MODELS; CAUSALITY; HUBBLE EFFECT; MAGNETIC MONOPOLES; METRICS; UNIFIED GAUGE MODELS; UNIVERSE; ELEMENTARY PARTICLES; MATHEMATICAL MODELS; MONOPOLES; PARTICLE MODELS; POSTULATED PARTICLES; 640106*  Astrophysics & Cosmology Cosmology
Citation Formats
Guth, A.H. Inflationary universe: A possible solution to the horizon and flatness problems. United States: N. p., 1981.
Web. doi:10.1103/PhysRevD.23.347.
Guth, A.H. Inflationary universe: A possible solution to the horizon and flatness problems. United States. doi:10.1103/PhysRevD.23.347.
Guth, A.H. 1981.
"Inflationary universe: A possible solution to the horizon and flatness problems". United States.
doi:10.1103/PhysRevD.23.347.
@article{osti_6981740,
title = {Inflationary universe: A possible solution to the horizon and flatness problems},
author = {Guth, A.H.},
abstractNote = {The standard model of hot bigbang cosmology requires initial conditions which are problematic in two ways: (1) The early universe is assumed to be highly homogeneous, in spite of the fact that separated regions were causally disconnected (horizon problem); and (2) the initial value of the Hubble constant must be fine tuned to extraordinary accuracy to produce a universe as flat (i.e., near critical mass density) as the one we see today (flatness problem). These problems would disappear if, in its early history, the universe supercooled to temperatures 28 or more orders of magnitude below the critical temperature for some phase transition. A huge expansion factor would then result from a period of exponential growth, and the entropy of the universe would be multiplied by a huge factor when the latent heat is released. Such a scenario is completely natural in the context of grand unified models of elementaryparticle interactions. In such models, the supercooling is also relevant to the problem of monopole suppression. Unfortunately, the scenario seems to lead to some unacceptable consequences, so modifications must be sought.},
doi = {10.1103/PhysRevD.23.347},
journal = {Phys. Rev., D; (United States)},
number = ,
volume = 23:2,
place = {United States},
year = 1981,
month = 1
}

A solution of Einstein's equations which admits radiation and a negativeenergy massless scalar creation field as a source is presented. It is shown that the cosmological model based on this solution satisfies all the observational tests and thus is a viable alternative to the standard bigbang model. The present model is free from singularity and particle horizon and provides a natural explanation for the flatness problem. We argue that these features make the creationfield cosmological model theoretically superior to the bigbang model.

Solution of the horizon and flatness problems by multiple inflations
A simple treatment is developed to describe a universe that has undergone successive generic inflations of the type described by us in a previous work. By comparing general expressions for the horizon and flatness problems it is shown that allowing ''failed'' inflationary bubbles within the visible universe results in values of ..cap omega.. that may depart logarithmically from unity. An exact relationship between a scale and which period of inflation determined its density perturbation amplitude is derived. Restricting attention to the case of double inflation, it is shown that many visible scales today fell within the event horizons of bothmore » 
Dynamical solutions to the horizon and flatness problems
We discuss in some detail the requirements on an earlyUniverse model that solves the horizon and flatness problems during the epoch of classical cosmology ([ital t][ge][ital t][sub [ital i]][much gt]10[sup [minus]43] sec). We show that a dynamical resolution of the horizon problem requires superluminal expansion (or very close to it) and that a truly satisfactory resolution of the flatness problem requires entropy production. This implies that a proposed class of adiabatic models in which the Planck mass varies by many orders of magnitude cannot fully resolve the flatness problem. Furthermore, we show that, subject to minimal assumptions, such models cannotmore » 
A First Principles Warm Inflation Model that Solves the Cosmological Horizon and Flatness Problems
A quantum field theory warm inflation model is presented that solves the horizon and flatness problems. The model obtains, from the elementary dynamics of particle physics, cosmological scale factor trajectories that begin in a radiation dominated regime, enter an inflationary regime, and then smoothly exit back into a radiation dominated regime, with nonnegligible radiation throughout the evolution. {copyright} {ital 1999} {ital The American Physical Society} 
Problems of singularity particle horizon and flatness in quantum cosmology
Classical relativistic cosmology is known to have the spacetime singularity as an inevitable feature. The standard big bang models have very small particle horizons in the early stages which make it difficult to understand the observed homogeneity in the universe. The relatively narrow range of the observed matter density in the neighbourhood of closure density requires highly fine tuning of the early universe. In this paper it is argued that these three problems can be satisfactorily resolved in quantum cosmology. It is shown that it is extremely unlikely that the universe evolved to the present state from quantum states withmore »