Variation of cosmological constant with time

In summary, in the paper "The Cosmological Constant" by Sean Carroll, the author discusses the Weinberg-Salam electroweak model and how it distinguishes between broken and unbroken symmetry phases. This leads to a difference in the effective cosmological constant in our current low-temperature epoch and in the early universe. The variation of the cosmological constant after symmetry breaking is considered real and accepted in standard cosmology. However, there is still limited discussion about its implications in cosmological models. Carroll's views on this are considered mainstream.
  • #1
kalish
28
0
Hello, in the paper from sean carroll "the cosmological constant" we can read this:
In the Weinberg-Salam electroweak model, the phases of broken
and unbroken symmetry are distinguished by a potential energy difference of approximately
MEW ∼ 200 GeV (where 1 GeV = 1.6 × 10−3 erg); the universe is in the broken-symmetry
phase during our current low-temperature epoch, and is believed to have been in the symmet-
ric phase at sufficiently high temperatures in the early universe. The effective cosmological
constant is therefore different in the two epochs; absent some form of prearrangement, we
would naturally expect a contribution to the vacuum energy today of order

Does this variation of the cosmological constant after symetry breaking is considered as real and accepted in standard cosmology? I find very few talks about a varying cosmological constant, and it is about border line theories. Is it set at the value actually observed in the whole evolution of the universe?

Best.
 
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  • #2
If you want us to discuss the paper, please give us a journal reference, or preferably a URL on arxiv.org.
 
  • #3
This is it. I happened to be looking for a variable cosmological 'constant' myself.

http://arxiv.org/abs/astro-ph/0004075

I think Carrolls views on this are mainstream, or at least not too near the left bank.
 
  • #4
I think this is also mainstream cause I read it in other papers, but I didn't find a discussion about the cosmological implication. This is kind of weird, If the current cosmological constant is really tiny, then how a tiny constant less a big contribution can not be negative and affect the cosmological models??
 

FAQ: Variation of cosmological constant with time

1. What is the cosmological constant and why does it vary with time?

The cosmological constant is a term in the equations of general relativity that represents the energy density of the vacuum of space. It was originally introduced by Einstein to explain the static universe, but later abandoned when the expansion of the universe was discovered. Recent observations have shown that the cosmological constant may not be constant and could vary with time due to the expansion of the universe and the influence of dark energy.

2. How does the variation of the cosmological constant affect the expansion of the universe?

The cosmological constant affects the expansion of the universe through its influence on dark energy. Dark energy is responsible for the accelerating expansion of the universe, and the variation of the cosmological constant can either enhance or suppress this expansion. A larger cosmological constant would lead to faster expansion, while a smaller one would result in slower expansion.

3. Is there evidence for the variation of the cosmological constant with time?

Yes, there is evidence for the variation of the cosmological constant with time. Observations of distant supernovae, the cosmic microwave background radiation, and the large-scale structure of the universe have all shown that the expansion of the universe is accelerating, indicating the presence of dark energy and a varying cosmological constant.

4. What are the implications of a varying cosmological constant for our understanding of the universe?

A varying cosmological constant has significant implications for our understanding of the universe. It challenges the traditional models of the universe and the role of dark energy in the expansion of the universe. It also raises questions about the nature of dark energy and its potential connection to other fundamental forces in the universe.

5. How do scientists study the variation of the cosmological constant with time?

Scientists study the variation of the cosmological constant with time through various observations and experiments. They use data from telescopes, satellites, and other instruments to measure the expansion rate of the universe and the effects of dark energy. They also use theoretical models and simulations to understand the underlying physics of the varying cosmological constant and its implications for the evolution of the universe.

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