Inflation.

Abstract

A short review of inflation is given, starting with a description of the underlying mechanism and the scenario of events. Four variations-old inflation, new inflation, chaotic inflation, and extended inflation-are discussed. It is claimed that the inflationary model provides a plausible explanation for (i) the large number of particles in the universe,(ii) the Hubble expansion, (iii) the large-scale uniformity of the universe, (iv) the nearness of the universe to a critical density, (v) the absence of magnetic monopoles, and (vi) the scaleinvariant spectrum of microwave background fluctuations observed by COBE (Cosmic Background Explorer). Finally, it is argued that the plausibility ofinflation is enhanced by the fact that inflation is eternal.The inflationary model is a modification of the standard big bang model that provides answers to a number of questions that the standard model fails to address. The inflationary period lasts for only a small fraction of a second, and then the inflationary model joins smoothly onto the standard model. The role of inflation is to set up the initial conditions for the standard model, conditions which otherwise would have to be assumed without explanation. Before inflation the total mass contained in the universe could have been as small as 10 kg. If inflation is right, then the inflationary mechanism is responsible for producing essentially all of the matter, energy, and entropy that exists in the universe today.In this lecture I will give a brief review of inflation, describing the mechanism of inflation, the outline of the scenario, the different types of inflationary models, and the evidence for inflation. Finally I will briefly discuss the eternal nature of inflation: once inflation begins, calculations indicate that it ends locally but not globally. Although this property does not appear to lead to any observable predictions, it certainly affects the way we think about the universe as a whole. I. The Mechanism of InflationBefore explaining the arguments for inflation, I will first explain how the inflationary model works.The mechanism of inflation depends on scalar fields, so I will begin by briefly summarizing the role of scalar fields in particle physics. To begin with, the reader should recognize that in the context of modern particle physics, all fundamental particles are described by fields. The best known example is the photon. The classical equations describing the electromagnetic field were written down in the 1860s, but then in the early 20th century physicists learned that the underlying laws of nature are quantum and not classical. The quantization of the electromagnetic field can be carried out in a very straightforward way. For simplicity one can consider the fields insideThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. a box, letting the size of the box approach infinity at the end of the c...

Cosmological surrealism: More than “eternal reality” is needed

“…Can we accept more than one reality, just as there are any number of reference frames? b) A similar situation arises in "Eternal" Inflationary Cosmology [3]. New universes can be created (e.g.…”

“…[1]. I would like to suggest that as a result of the recent advances in cosmological studies, in the context of the Inflationary Model [2,3], physics has effectively undergone yet another, perhaps its most profound revolution. This is conceptually comparable to the 1905 rejection of absolute time (the negation of absolute space was conceptually natural, as noted by Bishop Berkeley, by Newton himself and especially by Mach; the revolutionary aspect was limited in that case to the rejection of the Newtonian formalism).…”

“…Clearly, "eternity", as mentioned in Inflationary Cosmology [3] is not an adequate answer -it just relates to A, to the eternity of "our" reality. There is, however, (perhaps) a countable infinity of such "eternities", branching out from each other, then separating, with the offspring "hibernating" and never being born, in the parent universe's reality, to "the end of time" = our eternity.…”

Inflationary f (R) Cosmologies

“…To connect the scalar field φ with the Ricci-scalar R, we have to get t(R) from Eq. (16). Then after establishing φ(R), we can use the definition defined in Eq.…”

On Hybrid Wave Functions, Tidal Forces and Black Holes

“…However, there is still scope for time-variation of the value of the maximum attainable speed, as proposed by Guth [12] and expounded very clearly by Magueijo [13]. Such variation is not surprising, because the speed of light in a vacuum is fixed by the permittivity and permeability of empty space, and these properties, which relate to the transient production of virtual particles in the vacuum, can be expected to change quite dramatically as the available volume of vacuum varies from near-zero up to the present size of the universe.…”