# Inflationary universe: A possible solution to the horizon and flatness problems

## Abstract

The standard model of hot big-bang 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 elementary-particle 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:
- DE-AC03-76SF00515

- 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.. Thu .
"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 big-bang 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 elementary-particle 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 = {Thu Jan 15 00:00:00 EST 1981},

month = {Thu Jan 15 00:00:00 EST 1981}

}