Complete solution of the ΛCDM model problemsby petergreen Tags: big bang, cosmology, dark energy, dark matter, lambdacdm 

#1
Feb413, 09:39 AM

P: 25

Introduction: A new cosmology based on the production of massless particles (in the early de Sitter phase) and ΛCDM particles (in the transition to a late time de Sitter stage) has been discussed. The same mechanism avoids the initial singularity, particle horizon and the late time coincidence problem of the ΛCDM model has been phenomenologically eliminated (Λ ≡ 0) because there is no dark energy in accelerating scenario. In particular, this means that the dark energy component may be only a “mirage” (an effective description), since it can be mimicked (globally and locally) by the gravitationally induced particle production mechanism acting in the evolving Universe.
Published in Phys. Rev. D 86, 103534 (2012) [11 pages] http://link.aps.org/doi/10.1103/PhysRevD.86.103534 http://arxiv.org/pdf/1205.0868.pdf 



#2
Feb413, 01:52 PM

PF Gold
P: 1,493

sounds similar to this paper I had posted in an older thread.
http://arxiv.org/pdf/1212.1110v1.pdf 



#3
Feb413, 02:51 PM

P: 25

While the Lima CCDM model curve fits for the ΛCDM cosmology: And this explains the nature and formation of the dark matter. 



#4
Feb413, 04:27 PM

PF Gold
P: 1,493

Complete solution of the ΛCDM model problems
Last I heard ACDM had a 95% confidence level when looking at the large scale structure observations. OCDM had a similar confidence level, however ACDM had a larger confidence level than OCDM.
Not being too familiar with these models, Does this paper you posted increase those confidence levels? Keep in mind the papers I had on this subject were older lol 



#5
Feb513, 06:46 AM

Sci Advisor
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#6
Feb513, 07:18 AM

PF Gold
P: 717

Edit: sorry did not see Chalnoth's 



#7
Feb513, 09:14 AM

PF Gold
P: 1,493

The reference was from this paper
http://arxiv.org/pdf/astroph/0005476v1.pdf and yes I meant ΛCDM. I know what the terminology stands for just haven't figured out how to apply symbols that aren't on the quick symbol bar. In regards to the various cosmology models I'm still learning the subtle differences between them. Its quite a daunting task lol. As far as I understand it the ΛCDM model is the most accurate to other models such as OCDM, CHDM, TCDM and ΛCHDM. Are these other models now invalidated ? The other question I had is does the OP's paper address some of the inaccuracies described in the paper I posted to increase its accuracy in the model. The reason I'm asking is several of the cosmology text books I have are older but I'm currently studying them. There has been several sections I've found that new data has changed compared to what I have in those text books. The text I have is printed in 2006. Part of my self training in the math has been applying those new values to the provided formulas. 



#8
Feb513, 02:20 PM

P: 5,634

petergreen..thanks for the paper.....
I don't know all the math, but I like the conceptual framework: from THE FINAL REMARKS [Arxiv] edit: oops..I also wanted to post this from the Arxiv paper: "the merits of the particle creation scenario with respect to the usual DE ideology are a) the former has a strong physical basis namely nonequilibrium thermodynamics, while the latter (DE) has not and b) the particle creation mechanism uniﬁes the dark sector (dark energy and dark matter), since a single dark component (the dark matter) needs to be introduced into the cosmic ﬂuid and thus it contains only one free parameter. " Do you experts agree on the 'strong physical basis...thermodynamics"??....that would seem to be a big deal.... When does the " unstable de Sitter dominated phase" begin and do they explain how it got there?? 



#9
Feb513, 02:22 PM

Sci Advisor
P: 4,721

As for me, I copied and pasted from the Windows character map. Anyway, I think the main reason I was confused is that I did not understand your terminology. The way the paper states it is the way it's normally stated: "Current largescale structure data cannot rule out any of those models at 95% conﬁdence." That is to say, we never really are able to gain a probability value for the chance that a model is correct. The most we can do is continue to gather more and more experimental evidence that fails to show it incorrect. This paper shows that none of the large scale structure data is inconsistent with the standard cosmology or minor modifications of the standard cosmology. One can argue that we simply don't yet have enough data to show the problems of these models. But we now have enough independent sets of data to be sure that at the very least, the overall picture of ΛCDM is broadly correct, even if some details need to be changed. 



#10
Feb513, 02:48 PM

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#11
Feb513, 02:55 PM

P: 25





#13
Feb513, 07:51 PM

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