Inflation and initial conditions

In summary, the conversation discusses the issue of inflation in cosmology and the fine-tuning problem it presents. The question is posed whether a particular paper resolves this problem and if it refers to the same issue mentioned in the Wikipedia article. The person responding remains skeptical of the proposed solution and raises concerns about its feasibility.
  • #1
skydivephil
474
9
Its been argued that inflation needs the initial conditions to be finely tuned: eg:
http://en.wikipedia.org/wiki/Inflation_(cosmology)#Fine-tuning_problem
does this paper resolve this problem?

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-514R65K-2&_user=10&_coverDate=11%2F01%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3f86104ee19f80e65b0d9639614e0380&searchtype=a
 
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  • #2
skydivephil said:
Its been argued that inflation needs the initial conditions to be finely tuned: eg:
http://en.wikipedia.org/wiki/Inflation_(cosmology)#Fine-tuning_problem
does this paper resolve this problem?

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVN-514R65K-2&_user=10&_coverDate=11%2F01%2F2010&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=3f86104ee19f80e65b0d9639614e0380&searchtype=a
Well, personally, I remain extremely skeptical of the LQC bounce solution. The problem I have with it is that it so far seems to require a collapsing phase which is highly homogeneous and isotropic. But that is just incredibly unnatural, as any inhomogeneities pre-collapse will have been exacerbated as the collapse occurred.
 
  • #3
Sorry, I didnt mean to ask if the paper is a satisfactory solution or to assess LQC, merely to ask if the proposed solution is referring to the same problem as is mentioned in the wikipedia article.Or is it referring to something else? It seems to me to be the case, but as someone with no expertise in this field , I just wanted to check.
 

FAQ: Inflation and initial conditions

What is inflation and how does it relate to the initial conditions of the universe?

Inflation is a theoretical concept in cosmology that describes a period of rapid expansion of the early universe. It is thought to have occurred in the first fraction of a second after the Big Bang. The initial conditions of the universe refer to the state of the universe at the beginning of inflation, including its energy density, temperature, and density fluctuations.

What evidence supports the theory of inflation?

One of the main pieces of evidence for inflation is the observed homogeneity and isotropy of the universe on a large scale. This is known as the horizon problem, and inflation provides a solution by suggesting that the universe expanded rapidly and evenly at the beginning. Additionally, inflation predicts the existence of gravitational waves, which have been detected by the BICEP and Planck collaborations.

How does inflation help explain the flatness and smoothness of the universe?

The flatness and smoothness of the universe are two major problems in cosmology, as the laws of physics suggest that the universe should be much more curved and uneven than it actually is. Inflation solves these problems by stretching out the universe and smoothing out any irregularities, resulting in a flat and homogeneous universe.

What are the initial conditions necessary for inflation to occur?

In order for inflation to occur, the universe must have a high energy density and a scalar field with a non-zero potential. This scalar field is thought to be the source of the energy that drives inflation. In addition, the initial conditions must be such that the scalar field is in a state of slow roll, meaning it changes slowly over time.

Can inflation be tested or observed directly?

While inflation itself cannot be directly observed, its effects can be observed in the cosmic microwave background (CMB) radiation. The CMB is leftover radiation from the early universe and contains imprints of density fluctuations that were generated during inflation. By studying the CMB, scientists can gather evidence for or against different inflation models and test the theory indirectly.

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