Does lambda evolve?

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  • #1
jal
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Main Question or Discussion Point

Does lambda evolve?
Some people have been working on this question.

http://arxiv.org/abs/0801.1334
Collider Physics and Cosmology
Authors: Jonathan L. Feng
(Submitted on 8 Jan 2008)
====
http://arxiv.org/abs/0707.3778v1
Renormalization group running cosmologies - from a scale setting to holographic dark energy
Authors: Branko Guberina
(Submitted on 25 Jul 2007)
=======

http://arxiv.org/abs/gr-qc/0702087
Renormalization-group running cosmologies and the generalized second law
Authors: R. Horvat
(Submitted on 15 Feb 2007 (v1), last revised 22 Mar 2007 (this version, v3))
http://arxiv.org/abs/astro-ph/0404204
Holography and Variable Cosmological Constant
Authors: R. Horvat
(Submitted on 9 Apr 2004 (v1), last revised 8 Sep 2004 (this version, v4))
======
http://arxiv.org/abs/astro-ph/0407295
Accelerating Universe with a dynamic cosmological term
Authors: Saibal Ray, Utpal Mukhopadhyay, Xin-He Meng
(Submitted on 14 Jul 2004 (v1), last revised 4 Jun 2007 (this version, v2))
=====
http://arxiv.org/abs/astro-ph/0606448
Concerning the instantaneous mass and the extent of an expanding universe
Authors: H.J. Fahr, Michael Heyl
(Submitted on 19 Jun 2006 (v1), last revised 4 Dec 2006 (this version, v2))

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http://arxiv.org/abs/astro-ph/0606048
About universes with scale-related total masses and their abolition of presently outstanding cosmological problems
Authors: H.J. Fahr, M. Heyl
(Submitted on 2 Jun 2006 (v1), last revised 4 Dec 2006 (this version, v2))
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Cosmic vacuum energy decay and creation of cosmic matter.
Hans-Jörg Fahr, Michael Heyl
Argelander Institute for Astronomy, University of Bonn, 53121, Bonn, Germany, hfahr@astro.uni-bonn.de.
Source: Naturwissenschaften, Volume 94, Number 9, September 2007 , pp. 709-724(16)
Publisher: Springer
Abstract:
In the more recent literature on cosmological evolutions of the universe, the cosmic vacuum energy has become a nonrenouncable ingredient. The cosmological constant Λ, first invented by Einstein, but later also rejected by him, presently experiences an astonishing revival. Interestingly enough, it acts like a constant vacuum energy density would also do. Namely, it has an accelerating action on cosmic dynamics, without which, as it appears, presently obtained cosmological data cannot be conciliated with theory. As we are going to show in this review, however, the concept of a constant vacuum energy density is unsatisfactory for very basic reasons because it would claim for a physical reality that acts upon spacetime and matter dynamics without itself being acted upon by spacetime or matter.
=======
http://arxiv.org/abs/0803.2546
Primordial Entropy Production and Lambda-driven Inflation from Quantum Einstein Gravity
Authors: Alfio Bonanno, Martin Reuter
(Submitted on 17 Mar 2008)
“…the running cosmological constant _(k) changes by about 120 orders of magnitude between k-values of the order of the Planck mass and macroscopic scales,…

…. We are thus led to suspect that, because of the decreasing cosmological constant, there is a
continuous inflow of energy into the cosmological fluid contained in an expanding Universe…

…. The assumption that the matter system must allow for an unhindered energy exchange with _
is essential, see refs. [25, 27]….”
-----------------
http://arxiv.org/abs/0708.1317
Functional Renormalization Group Equations, Asymptotic Safety, and Quantum Einstein Gravity
Authors: Martin Reuter, Frank Saueressig
(Submitted on 9 Aug 2007)
http://arxiv.org/abs/0709.3851
Asymptotic Safety
Authors: R. Percacci
(Submitted on 24 Sep 2007)


http://xxx.lanl.gov/abs/hep-th/0603022
Quantum gravity and the standard model
Authors: Sundance O. Bilson-Thompson, Fotini Markopoulou, Lee Smolin
(Submitted on 3 Mar 2006 (v1), last revised 21 Apr 2007 (this version, v2))
=======
jal
 

Answers and Replies

  • #2
Kea
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There is no [itex]\Lambda[/itex], classically speaking. No Dark Force. Zippo. Nada. Done away with.
 
  • #3
Demystifier
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There is no [itex]\Lambda[/itex], classically speaking. No Dark Force. Zippo. Nada. Done away with.
What is that suppose to mean? :confused:

By the way, I have also been working on that problem, as a coauthor with some of the authors mentioned above. I believe that it is safe to say that the answer to the question "Does Lambda evolve?" is not yet clear.
 
  • #5
jal
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Hi Demystifier
Would you be able to tell us which approach you are working on?
Would you have some links of other approaches, (which I would like to read).
jal
 
  • #6
Kea
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By the way, I have also been working on that problem, as a coauthor ....
And as I pointed out some years ago in a short paper, referenced in the above papers, although the association of q-deformation with [itex]\Lambda[/itex] may appear to suggest a positive, or indeed variable value, the classical limit inevitably drives [itex]\Lambda[/itex] towards zero in the emergent spacetime. See also Lunsford, Riofrio, Pitkanen, Wiltshire et al. They all have compelling explanations for a zero CC.
 
  • #7
Haelfix
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Umm, there is no good reason why lambda should be zero theoretically, either at the classical level or at the quantum level.

Before the Supernova and CMB measurements erased most hope for an identically zero CC, people were desperatedly trying to find a good mechanism (say a symmetry principle) to make it zero. None were found, and various theorems preventing plausible zero scenarios were written down. That is why Weinberg, in frustration, wrote down his now infamous anthropic paper.

If people could make it go away, everyone would jump on the solution b/c it is so unlovely aesthetically.
 
  • #8
Kea
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Before the Supernova and CMB measurements erased most hope for an identically zero CC, people were desperatedly trying to find a good mechanism (say a symmetry principle) to make it zero. None were found ...
People should look harder. People should be jumping on this option. Of course it has to come from a quantum gravitational principle, because its not in GR or the SM. All of the abovementioned ideas use related variants of a Machian holographic principle - but not a string theoretic one.
 
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  • #9
jal
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Hi Kea
You made me work hard. (It wasn't needed/justified)
Are these the papers that you are referring.
http://arxiv.org/abs/0712.3984
Dark energy without dark energy
Authors: David L. Wiltshire
(Submitted on 24 Dec 2007)

p. 28
If one replaces the words “dark energy” by “voids” in the standard qualitative
explanation, then a probable description of the ISW effect in the FB model
emerges.

A true “concordance cosmology” should agree with all reliable observations,
and not just a carefully selected subset. A glance at Table 2 reveals that
there are many anomalies in the standard _CDM model.

http://arxiv.org/abs/gr-qc/0503099
Viable inhomogeneous model universe without dark energy from primordial inflation
David L. Wiltshire
(Submitted on 23 Mar 2005 (v1), last revised 11 Jul 2005 (this version, v5))
Citation of this earlier work (21)
http://www.citebase.org/search?type=identifier&submitted=Cited+By&identifier=oai%3AarXiv.org%3Agr-qc%2F0503099 [Broken]
 
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  • #10
Kea
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That's a start, although this analysis is purely classical.
 
  • #11
jal
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p. 28
If one replaces the words “dark energy” by “voids” in the standard qualitative
explanation, then a probable description of the ISW effect in the FB model
emerges.
Coincidence on a cosmic scale does not "just" happen.
Has anyone looked at and analyzed the fact that the "bubbles' are "coincidently" the same as sphere packing? What is the mechanism causing this?
jal
 
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  • #12
Kea
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anyone looked at and analyzed the fact that the "bubbles' are "coincidently" the same as sphere packing? What is the mechanism causing this?
jal
The question is: what exactly do you mean by the phrase the same as sphere packing? Now I happen to be interested in the mathematics of sphere packing, partly for cosmological reasons as you say, but there are a LOT of details in between that and this.
 
  • #13
I believe jal, if I understand you correctly, that what you're trying to get at with the sphere and sphere packing model might be something like this, let's say you have an atom or a bauble or a pearl and when you super position the nucleic substance only half of the most outer layer shells enters a corporeal phaseout state of infinite possibility's all relying on the one flat constant concrete charge to fix void from, underlined in possibility of chance and catastrophe. Eventually the possibilities would begin to collapse and cause a dark fix infiltrative time tear to begin to open on the positive space side and export the particles to and through to the other side in order to undergo the process of certain possibility discontinuation. The infinite and unknown possibilities remaining in the bauble achieve a state of regressed time inversion independent of either side. The photons are spliced, inverted and travel, rise and engage in an internal concentrated bubble of a corporeal phaseout. Zero point gravity is inside the holo shell, the outer magnetically exploded and expanded edges are the 'Inra In Bows' of potentials, possibility and chance. A bubble rising out in cylinder from within a triple helix spiral, or a trinity of the genome finally ascending...:uhh:

But of course you certainly know much more than I do and I'm just learning :redface:
Tell me what you think, if anything?

Does lambda evolve? My point says yes...

-Pictosurial Dreamlog
 
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  • #14
jal
549
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Pictosurial
Sorry but your eloguent description did not evoke anything in me. (No associations) :confused:
Welcome!

Kea
there are a LOT of details in between that and this.
I raised the point for the very reason that it would take knowledge that I do not possess to be able to try to identify a possible mechanism.
 
  • #15
Ok so let me setup a geometric mathematical provocation.

Combine, catalog, symbolize and mutate or fuse the following...
+1³ gnomonic stance
-1³ gnomonic dance
A square within a circle
An open six space cube
A hypercube balanced within the chrono cross
A hexagon holo by cube
A time riddled specter in phaseout fugue
The triple helix spiral all rising out of and into man's room

Holographic double imaging principles and strings are all in full effect here as is synesthesia and man's pictorial amnesia...

Now try harder and give me some thoughts...:shy:
 
  • #16
Kea
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Combine, catalog, symbolize and mutate or fuse the following...
Any mathematician could easily do that. Such loose terms are not relevant to this discussion.
 
  • #17
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(...) All of the abovementioned ideas use related variants of a Machian holographic principle - but not a string theoretic one.
Hi Kea,

Interesting that you mention this. I've started working on a "Machian holographic-like" principle in the context of Braneworlds some years ago. The braneworld scenario served just as an exercise. The idea does not necessarily need, in a fundamental way, the braneworld.

http://xxx.lanl.gov/abs/gr-qc/0411038
A Note on the Integral Formulation of Einstein's Equations Induced on a Braneworld
Gen.Rel.Grav. 37 (2005) 959-965

I did not get back to these ideas, but I intend to, as soon as I find more time.

Best,
Christine
 
  • #18
jal
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Hi ccdantas
You have a lot of good references.
http://xxx.lanl.gov/abs/gr-qc/0411038
A Note on the Integral Formulation of Einstein's Equations Induced on a Braneworld
Authors: Christine C. Dantas
(Submitted on 8 Nov 2004)
We argue that the role of the surface term (the sourcefree contribution) in the braneworld scenario may be quite subtler than in the 4D formulation. This may pose, for instance, an interesting issue to the cosmological constant problem.
----------
Question
I could not help but noticed that if instead of using the Randall-Sundrum type 2 model [14], description, could you replace it with Schwarzschild radius, event horizon, cosmic horizon to achieve the same thing. H.J. Fahr and Michael Heyl seem to have done something similar.
--------
One of your references, R. G. Vishwakarma, has continued publishing interesting papers.
http://lanl.arxiv.org/find/gr-qc/1/au:+Vishwakarma_R/0/1/0/all/0/1
since publishing
http://lanl.arxiv.org/abs/gr-qc/0205075
A Machian Model of Dark Energy
Authors: R. G. Vishwakarma
(Submitted on 17 May 2002 (v1), last revised 19 Aug 2002 (this version, v2))

This forces one to think whether the Mach's ideas and the cosmological constant are interrelated in some way.
--------
http://lanl.arxiv.org/abs/astro-ph/0211285v3
Can brane cosmology with a vanishing \Lambda explain the observations?
Authors: R. G. Vishwakarma (IUCAA), Parampreet Singh (IUCAA)
(Submitted on 13 Nov 2002 (v1), last revised 21 Mar 2003 (this version, v3))
It should be noted however that despite its consistency with the observations, the nature of dark energy is a mystery at present. It does not seem to resemble any known form of matter tested in the laboratory. As yet, we have no direct indication that it really exists. In fact, a more natural value of the cosmological constant is zero (which could either be due to some symmetry or due to a dynamical adjustment
mechanism) rather than an extremely small value but still non-zero.
In this paper, we show that the present observations …. can successfully be explained without a lambda term and the universe is still decelerating.

His latest
http://lanl.arxiv.org/abs/0801.2973
A Model to Explain Varying $\Lambda$, $G$ and $\sigma^2$ Simultaneously
Authors: R. G. Vishwakarma
(Submitted on 18 Jan 2008)
------
When I check the citations, I find other authors who have been dealing with the subjects of this thread.
jal
 
  • #19
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Hi jal,

What I meant was that you can use the integral formulation of Einsteins equations in other contexts. The main problem is to give a precise meaning to Mach's Principle. The integral formulation provides that to a certain extent.

Christine
 
  • #20
Kea
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The main problem is to give a precise meaning to Mach's Principle. The integral formulation provides that to a certain extent.
Hi Christine. Yes, I recall your paper. Constraining allowed spacetimes in this way is one concrete implementation of a Machian principle. I expect that the GR limit of QG will come with such constraints attached. Thus GR is viewed as 'incomplete' as a theory.
 
  • #21
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I expect that the GR limit of QG will come with such constraints attached.
Yes, I agree 100% with you here. But Mach's principle seems to be neglected these days. The problem of quantum gravity is the problem of inertia, IMO.
 
  • #22
Kea
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But Mach's principle seems to be neglected these days.
Hopefully the experimental facts will eventually seep into the consciences of theorists, like a sledge hammer.
 
  • #23
Chronos
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What experiments do you have in mind, Kea, online or proposed?
 
  • #24
Demystifier
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Hi Demystifier
Would you be able to tell us which approach you are working on?
I have been working on combining the idea of holography with the idea of renormalization group in effective field theory to study the running of the cosmological "constant":
http://xxx.lanl.gov/abs/astro-ph/0507666
http://xxx.lanl.gov/abs/astro-ph/0601598
http://xxx.lanl.gov/abs/astro-ph/0611299
More recently, I have been working on an approach based on the trace anomaly
http://xxx.lanl.gov/abs/0707.3830
 
  • #25
Kea
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What experiments do you have in mind?
Sigh. The question is: what are you willing to take as convincing evidence? Very few people would give up their prejudices about cosmology based on one anomaly alone, such as the idea of the Dark Force itself. In fact, we are talking about the opposite extreme: looking at all pieces of evidence and comparing anomalies on either side. The problem with this is that a LOT of people work on LCDM, but very, very few people work on radical alternatives. So when somebody comes up with a big list of LCDM anomalies that can all be explained away by the more radical alternative, the natural human reaction appears to be that it cannot possibly be right, because not enough people have checked all the details. So how do all the details get checked? Well, obviously, the old people die and younger people realise that some new ideas are worth investigating. It takes time.

Now at least read some of the work mentioned.
 

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