Acceleration of a universe with -ve Cosmological Constant

In summary, the conversation discussed a new paper by Stephen Hawking and colleagues that uses wavefunctions to demonstrate the acceleration of a universe with lambda<0, which is consistent with string theory and quantum mechanics. The technique bridges the gap between quantum mechanics and general relativity. The speaker also requested feedback on the paper and provided links for further information and discussion.
  • #1
shreyakmath
41
0
I have read this new paper by Stephen Hawking and collegues.
It is very interesting to see the use of wavefunctions to show the acceleration of a universe with lambda<0 which fits in the framework of string theory and quantum mechanics. This technique bridges quantum mechanics and general relativity to a satisfactory level.

I wish to have your feedback on the paper.
The link is below:

http://arxiv.org/abs/1205.3807
 
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  • #2
shreyakmath said:
I have read this new paper by Stephen Hawking and collegues.
It is very interesting to see the use of wavefunctions to show the acceleration of a universe with lambda<0 which fits in the framework of string theory and quantum mechanics. This technique bridges quantum mechanics and general relativity to a satisfactory level.

I wish to have your feedback on the paper.
The link is below:

http://arxiv.org/abs/1205.3807

We already have a thread commenting on this paper:
https://www.physicsforums.com/showthread.php?t=606988
The thread is just a little ways down the menu from yours (about 16 or 17 items down) and it is called "Accelerated Expansion from Negative Lambda".

"MTd2" started the thread in mid-May as soon as the paper appeared and Brian Powell immediately made an intelligent observation:
bapowell said:
Yes. This might just be the adrenaline needle getting plunged into the heart of string theory.

Basically, I think, we are waiting to see what the professional string research community does with this: whether (after this shot of adrenaline) the apparently dead body on the operating table gets up and walks away :biggrin:
 
Last edited:
  • #4
Ok. Thanx
 

1. What is the Cosmological Constant?

The Cosmological Constant is a term in Einstein's theory of general relativity that represents the energy density of the vacuum of space. It is often denoted by the Greek letter lambda (Λ) and is used to explain the observed acceleration of the expansion of the universe.

2. How does the Cosmological Constant affect the acceleration of the universe?

The Cosmological Constant has a positive effect on the acceleration of the universe. It is believed that this constant causes the expansion of the universe to accelerate, rather than slow down, as would be expected due to the gravitational pull of matter. This theory is supported by observational evidence, such as the observation of distant supernovae.

3. What is the role of negative Cosmological Constant in the acceleration of the universe?

A negative Cosmological Constant would have the opposite effect and would cause the expansion of the universe to decelerate. However, current observations suggest that the Cosmological Constant has a positive value, indicating that the expansion of the universe is accelerating.

4. Can the acceleration of the universe be explained without the Cosmological Constant?

There have been various theories proposed to explain the acceleration of the universe without the need for a Cosmological Constant. These include theories involving modifications to general relativity or the presence of a new form of energy called dark energy. However, the Cosmological Constant remains the most widely accepted explanation for the observed acceleration.

5. What are the implications of an accelerating universe with a negative Cosmological Constant?

If the universe had a negative Cosmological Constant, it would likely lead to a decelerating expansion and a different fate for the universe. It is possible that the universe would eventually stop expanding and start contracting, potentially leading to a "big crunch" where the universe collapses in on itself. However, more research is needed to fully understand the implications of a negative Cosmological Constant on the fate of the universe.

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