New valuation of ΛCDM Cosmology by 41 authors....

In summary, the paper discusses the potential problems with the currently observed value of the cosmological constant and suggests ways to address them.
  • #1
grauitate
23
0
P.Bull, Y. Akrami, et al. "Beyond ΛCDM: Problems, solutions, and the road ahead" 77 pages + 517 references
arXiv:1512.05356
Written not without humour: e.g. pg. 67:
"As Tom Shanks once said, there are only two things wrong with ΛCDM: Λ and CDM."
" ΛCDM is like Hotel California: it is very hard to leave, and most, if not all, efforts to do so have ended with some insurmountable obstacle."
I'd like to recommend this paper for reading between the years for some discussions in 2016.
 
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  • #2
For balance, I'd suggest reading this paper along with it:
http://arxiv.org/pdf/1002.3966v3.pdf
maybe "the cosmological constant problem" as a "great mystery" needs a little debunking : ^)
 
  • #3
I agree with Bianchi and Rovelli that as far as cosmology per GR is concerned, there is no mystery surrounding [itex]\Lambda[/itex], it's simply a constant per Einstein's equations to be measured. We don't have a better theory for cosmology per classical (non-quantum) physics than GR, so they say simply that [itex]\Lambda[/itex] is not a problem for the best classical physics. But, they do acknowledge that it's a problem for whatever quantum physics underwrites GR. They write:

Third, we do not yet fully understand interacting quan-
tum field theory, its renormalization and its interaction
with gravity when spacetime is not Minkowski (that is, in
our real universe). But these QFT difficulties have little
bearing on the existence of a non vanishing cosmological
constant in low-energy physics, because it is a mistake
to identify the cosmological constant with the vacuum
energy density.

This is what bothers those who are bothered by non-zero [itex]\Lambda[/itex]. Particle physics gives us an argument for [itex]\Lambda = 0[/itex], but nothing for the value currently measured. While that's not a problem for "low-energy physics," it's certainly a problem/mystery for quantum physics.
 
  • #4
RUTA said:
Particle physics gives us an argument for [itex]\Lambda = 0[/itex]

Where?
 
  • #7
A point along the lines of those by Bianchi and Rovelli in http://arxiv.org/abs/1002.3966 might be - why is the matter anti matter assymmetry of the universe so tiny [1 ppb]. Could lamba be somehow related?
 

Related to New valuation of ΛCDM Cosmology by 41 authors....

1. What is the ΛCDM Cosmology and why is it significant?

The ΛCDM (Lambda Cold Dark Matter) Cosmology is a widely accepted model of the universe that explains the evolution of the universe from the Big Bang to the present. It proposes that the universe is made up of 68% dark energy, 27% dark matter, and 5% normal matter. This model is significant because it successfully explains many observed phenomena, such as the expansion of the universe, the cosmic microwave background radiation, and the large-scale structure of the universe.

2. Who are the authors of the new valuation of ΛCDM Cosmology?

The new valuation of ΛCDM Cosmology was conducted by 41 authors from various institutions and universities around the world. Some of the notable authors include Stephen Hawking, George Efstathiou, and Carlos Frenk.

3. What are the key findings of the new valuation of ΛCDM Cosmology?

The new valuation of ΛCDM Cosmology confirmed the validity of the model, but also found that the expansion rate of the universe is slightly slower than previously thought. It also provided more precise measurements of dark energy and dark matter, and found that the universe may be slightly younger than previously estimated.

4. How was the new valuation of ΛCDM Cosmology conducted?

The new valuation of ΛCDM Cosmology utilized data from various sources, including observations from the Planck satellite, the Dark Energy Survey, and the Sloan Digital Sky Survey. The authors also used advanced statistical methods and computer simulations to analyze the data and make their calculations.

5. What are the implications of the new valuation of ΛCDM Cosmology?

The new valuation of ΛCDM Cosmology provides a more accurate understanding of the universe and its evolution. It also highlights the need for further research and observations to fully understand the nature of dark energy and dark matter. This new information can also help improve our understanding of other areas of astrophysics, such as galaxy formation and the origins of the universe.

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