Cosmology during inflation

How big did the universe get during inflation?
Prior to that, the model suggests that there was a brief period of extraordinarily rapid expansion or inflation, during which the scale of the universe increased by a factor of about 1050 times more than predicted by standard Big Bang models (Figure 29.6. 1).
Figure 29.6..
What part of the universe expanded during inflation?
During inflation, the cosmic scale factor grows exponentially in time.
In order to solve the horizon and flatness problems, inflation must have lasted long enough that the scale factor grew by at least a factor of e⁶⁰ (about 10²⁶)..
Inflation is an extension of the Big Bang theory in which the universe expanded from an atomic scale to a cosmic scale in a fraction of a second, making the universe geometrically flat.
The ekpyrotic scenario.
In this alternative to inflationary cosmology, the universe we inhabit is confined to one of two sheets that represent four-dimensional branes bounding a five-dimensional spacetime.

During inflation, the energy density in the inflaton field is roughly constant. However, the energy density in everything else, including inhomogeneities, curvature, anisotropies, exotic particles, and standard-model particles is falling, and through sufficient inflation these all become negligible.

The inflationary Universe According to the theory of inflation, the early Universe expanded exponentially fast for a fraction of a second after the Big Bang. Cosmologists introduced this idea in 1981 to solve several important problems in cosmology. One of these problems is the horizon problem.

Overview

One of the more enduring contributions of particle physics to cosmology is the prediction of inflation by the American physicist Alan Guth and others.
The basic idea is that at high energies matter is better described by fields than by classical means.
The contribution of a field to the energy density (and therefore the mass density) and the pressure of the vacuum state need not have been zero in the past, even if it is today.
During the time of superunification (Planck era, 10−43 second) or grand unification (GUT era, 10−35 second), the lowest-energy state for this field may have corresponded to a “false vacuum,” with a combination of mass density and negative pressure that results gravitationally in a large repulsive force.
In the context of Einstein’s theory of general relativity, the false vacuum may be thought of alternatively as contributing a cosmological constant about 10100 times larger than it can possibly be today.
The corresponding repulsive force causes the universe to inflate exponentially, doubling its size roughly once every 10−43 or 10−35 second.
After at least 85 doublings, the temperature, which started out at 1032 or 1028 K, would have dropped to very low values near absolute zero.
At low temperatures the true vacuum state may have lower energy than the false vacuum state, in an analogous fashion to how solid ice has lower energy than liquid water.
The supercooling of the universe may therefore have induced a rapid phase transition from the false vacuum state to the true vacuum state, in which the cosmological constant is essentially zero.
The transition would have released the energy differential (akin to the “latent heat” released by water when it freezes), which reheats the universe to high temperatures.
From this temperature bath and the gravitational energy of expansion would then have emerged the particles and antiparticles of noninflationary big bang cosmologies.

What is cosmic inflation theory?

The Cosmic Inflation Theory was developed by particle physicist Alan Guth during the early 1980s to deal with the three problems presented by the Big Bang Theory.
He theorized that the reason why the Universe appears to be flat is because of the extremely fast rate at which it grew.

What is inflationary cosmology?

Inflationary cosmology is a highly successful framework for exploring these interconnections between particle physics and gravitation.
Inflation makes several predictions about the present state of the universe—such as:

its overall shape

large-scale smoothness

and smaller scale structure—which are being tested to unprecedented accuracy by ..

What is the inflationary theory of cosmology?

Inflationary theory predicts a flat universe, and a flat universe predicts that these fluctuations should be greatest on a one-degree scale.
This is what WMAP found, confirming the flatness of the cosmos and providing evidence in support of inflation.
But how did inflation happen? .

What is the theory of inflation?

The theory holds that the basic explanation for inflation is the fact that some producers, group of workers or both, s쳮d in raising the prices for either their product or services above the levels that would prevail under more competitive conditions.