- #106
RUTA
Science Advisor
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marcus said:Well. That's how the real world operates It's not a big deal. Better to get your message out with a little distortion than not to reach the Nature journal audience.
Absolutely!
marcus said:Well. That's how the real world operates It's not a big deal. Better to get your message out with a little distortion than not to reach the Nature journal audience.
atyy said:I agree in general that there is a fine tuning problem with the cc coming from quantum effects. But I thought the Casimir effect isn't evidence of this since it can be calculated without using zero-energy, like in http://arxiv.org/abs/hep-th/0503158?
Physics Monkey said:I always found it interesting that Jaffe's paper does not mention what might be called the topological Casimir effect. In this case the fields are confined by the topology of compact space instead of by any "perfectly conducting sheets" and so forth. Naively, it seems that there is no coupling dependence in such a situation.
marcus said:Or you could just think of Λ as the zero-point curvature that is intrinsic to nature's geometry.
And as curvature that would be an inverse area, so that 1/Λ is an area.
And therefore 1/√Λ is a length.
Which length we believe to be 9.3 billion LY based on the large amount of supernova data which has accumulated.
...
atyy said:Bianchi and Rovelli are not saying anything new, are they? Take eg. this 2007 review
http://arxiv.org/abs/0705.2533
"The observational and theoretical features described above suggests that one should consider cosmological constant as the most natural candidate for dark energy. Though it leads to well known problems, it is also the most economical [just one number] and simplest explanation for all the observations. Once we invoke the cosmological constant, classical gravity will be described by the three constants G, c and Lambda"
atyy said:Padilla mentions the Galileon stuff in the introduction of his PRL paper, and says that it is closely related. The Galileon stuff was originally motivated by DGP - which passed First-Year Sloan Digital Sky Survey-II (SDSS-II) Supernova Results: Constraints on Non-Standard Cosmological Models.
marcus said:Good point! What about his current paper? The March 2012 one.
atyy said:Hmmm, seems unrelated to the Fab Four idea.
Marcus said:What ( Kimpton and Padilla) are talking about ...is a mathematical
technique to "degravitate" the QFT vacuum energy ...