https://www.researchgate.net/publication/317341105_A_Review_on_Cosmic_Inflation
Abstract:
The Standard Big Bang Cosmology gives the most accepted concept about the beginning and evolution of the Universe. However, it has problems: the flatness problem, the horizon problem and the monopole problem. The predictions of the Standard Big Bang Cosmology do not match the observations of modern cosmologists. Nonetheless, the admirers of the Standard Big Bang Cosmology continued to find out ways for solving those problems and such attempts lead to our knowledge of Inflationary Cosmology. The theory of inflation, which was first proposed by Alan Guth in 1981, soon became a “need” of modern cosmology and various modified models of inflationary Universe were proposed. In this paper, the author gives a brief insight of the Standard Big Bang Cosmology, introduces inflationary cosmology with its brief background, reviews some concepts associated with cosmic inflation, explains how inflation can be classified into various types, describes few of the popular types in brief and explains how the cosmological problems are solved by cosmic inflation. Moreover, few insightful examples have been given to easily explain the fundamental concepts so that even a junior researcher can get thorough idea about the field by escaping the equations and simply going through the text selectively.
extract:
Creation of the Universe from nothing
Even though all the matter in the Universe including
rocks, planets, stars, galaxies, quasars, black holes and
clusters is huge and positive, the energy stored within
gravity may be negative which means the sum could add
nearly to zero. This means that creation of such Universe
from nothing doesn‟t violate the Conservation of Energy.
The very idea of creating Universe from nothing was
introduced by Edward Tryon who believed that the
Universe “happens from time to time” as a result of
quantum fluctuations in vacuum (MichioKaku, 2004).
The Universe-from-nothing theory is significant to
answer practical questions about why the Universe
doesn‟t spin and why the total spin of all the galaxies in
the Universe cancels out.
Conclusive words with hypothesis:
Chaotic inflation is a much better model of inflation as it
doesn‟t require fine tuning unlike the new and old
inflationary theories. The idea of eternal inflation seems
reasonable and the fact that dark matter and dark energy
can be used as some sort of indications of existence of
parallel Universes-can be useful to support eternal
inflation theory. Even though this hypothesis isn‟t
verifiable, dark matter could be the effect of a parallel
Universe which co-exists with ours. It could be the result
of some higher dimensional Universe from where our
Universe is visible but to whom we cannot see, just like
an imaginary 2D TV character having height and width
as the dimensions cannot see us in the dimension of
depth. If that is the case, dark matter and dark energy
could just be some higher dimensional features which
have been unleashed to our Universe by the co-existing
higher-dimension Universe. That being the case, the
inflation field (which can actually resemble the
Cosmological Constant or Dark Energy in some ways
can be the result of the influence of higher dimension. A
string-theory approach to test this hypothesis will be
much appreciable in the future of Cosmology.
However,
a better approach is to deliver a mechanism that can be
theoretically possible and experimentally verifiable.
If the early Universe had a rapid spin, the so-produced
centrifugal force could rip apart many parts and throw
them away. The space could have expanded in similar
manner and inflation could indeed be not required. A
sudden centrifugal force could have led to some sort of
exponential expansion which was stopped very soon by
the release of massive amount of energy in the process. If
that is the case, Cosmic Inflation is more of a Cosmic
Rotation and the inflation field is more of a Rotation
Virtual Field. Even though this idea may seem unlikely,
the extreme temperature in the early ages of the Universe
could have triggered such mechanism. This is definitely
testable and verifiable at least within couple of decades.
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Interesting to say the least.