DeSitter and AntiDeSitter Universe

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The discussion centers on the DeSitter and AntiDeSitter universes, particularly in relation to the Friedmann-Lemaître-Robertson-Walker (FLRW) model, which remains relevant for describing a homogeneous and isotropic universe with positive cosmological constant (Lambda). The Lambda Cold Dark Matter (ΛCDM) model is highlighted as the current framework for this scenario. For inhomogeneous and anisotropic early universe conditions, the conversation suggests that the FLRW metric still applies, although it may require modifications to account for primordial density fluctuations. Additionally, the AntiDeSitter (AdS) model is mentioned in the context of string theory and the AdS/CFT correspondence, though details on its workings are less explored. Overall, the discussion emphasizes the ongoing relevance of established models while acknowledging the complexities of early universe conditions and theoretical frameworks.
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If the DeSitter Universe is modeled by Empty Universe
1. Very Early Universe with Inflaton Field
2. Very Far Universe in Future when Black Holes have evaporated
 
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Q1
What Einstein model currently describes a Homogeneous and Isotropic approximated Universe with Matter with positive Lambda, is it still Friedmann (FLRW) or have models moved on

Which Einstein model describes an Inhomogeneous and Anisotropic very early universe with primordial density fluctuations
 
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Q2

Are there any scenarios for an AntiDeSitter Model in the chronology of the Universe
 
Quantizer said:
Q1
What Einstein model currently describes a Homogeneous and Isotropic approximated Universe with Matter with positive Lambda, is it still Friedmann (FLRW) or have models moved on

Which Einstein model describes an Inhomogeneous and Anisotropic very early universe with primordial density fluctuations

Its still the FLRW metric or more specifically the LCDM model, \LambdaCDM. Which also involves the Eintein field equations..
as far as the De-sitter universe usages you will probably be interested in this article.

De-Sitter musings

http://arxiv.org/abs/1205.3855

also a string theory model variant uses ADS.
ADS/CFT Anti-Desitter correspondance I'm not too familiar with how this model works yet to supply any details.
 
Mordred said:
Its still the FLRW metric or more specifically the LCDM model, \LambdaCDM. Which also involves the Eintein field equations..
as far as the De-sitter universe usages you will probably be interested in this article.

De-Sitter musings

http://arxiv.org/abs/1205.3855

also a string theory model variant uses ADS.
ADS/CFT Anti-Desitter correspondance I'm not too familiar with how this model works yet to supply any details.
Thanks for that Mordred, a few pages in and already intrigued by some of the astronomical exponentials being put forward
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
The formal paper is here. The Rutgers University news has published a story about an image being closely examined at their New Brunswick campus. Here is an excerpt: Computer modeling of the gravitational lens by Keeton and Eid showed that the four visible foreground galaxies causing the gravitational bending couldn’t explain the details of the five-image pattern. Only with the addition of a large, invisible mass, in this case, a dark matter halo, could the model match the observations...
Hi, I’m pretty new to cosmology and I’m trying to get my head around the Big Bang and the potential infinite extent of the universe as a whole. There’s lots of misleading info out there but this forum and a few others have helped me and I just wanted to check I have the right idea. The Big Bang was the creation of space and time. At this instant t=0 space was infinite in size but the scale factor was zero. I’m picturing it (hopefully correctly) like an excel spreadsheet with infinite...
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