Journal club
76. Chaos in quantum field theory
Clearly, the topic of interplay between confinement and chaos in classical YM got some interest, so let me continue. Contrary to what the title says, I shall not mention “confinement” this time, focusing on “chaos” instead.
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75. Chaos in YM and confinement
I think we are currently having a somewhat fruitful discussion with Marco Frasca on his blog. The question is how relevant is chaotic behavior of classical solutions of Yang-Mills equations of motion for the quantum theory (or, more precisely, for YM at strong coupling).
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73. How eukaryotic cells feel direction
Eukaryotic cells present in both plants and animals are cells bounded by membranes and containing nuclei.
Often they contain other organelles such as mitochondria or chloroplasts, but this is not what will interest us at this time – let us focus on membranes.
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71. More talks: M2 branes and AdS/CFT, correlations of low multipoles in CMB
Here is another couple of recent talk at Perimeter Institute worth if not watching, but at least going through the presentation file:
1. Igor Klebanov from Princeton discusses M2 branes and AdS/CFT correspondence. M2 branes are very hot topic in string theory now (see the review of membrane minirevolution on the Lubos Motl’s blog). Let me remind you that M2 branes are supermembranes in 11-dimensional M-theory, and one naturally wants to get a kind of AdS/CFT considering world volume theory on them. Generally, this should be more complicated than the construction of 
duality, since the M-theory is inherently strongly coupled, while the analysis of the 10-dim. string theory is well under control at least in the regime of weak coupling.
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69. Happy Halloween!
Since it is Halloween, today’s story is about ghosts…
Let us follow the analysis of massive gravity theory in de Sitter background by Izumi and Tanaka.
The action of the theory is given by
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67. Weak lensing and modifying gravity
Jochen Weller et al. are trying to constrain the modified gravity theories with weak lensing data combined with baryon acoustic oscillations and supernovae data. Namely, the authors are mostly interested to fit the Dvali-Gabadadze-Porrati model and its modification mDGP (one parametric matching between Lambda CDM and DGP).
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66. Some interesting talks worth watching
Steve Carlip talks about topologically massive gravity at Perimeter, namely, about 3d topologically massive gravity in AdS and finds that it is unstable (even for chiral values Strominger mentioned at Strings 08).
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65. Simulations of decaying turbulence
A group of people (with Jonathan Dursi being the only one I know personally among them) has written nice review of existing software for stimulating decaying compressible (supersonic) turbulence with the goal to compare performance of the codes. In particular, they have reviewed GADGET, PHANTOM, VINE, ENZO, FLASH, TVD, and ZEUS (the first three being SPH, i.e., particle codes, while the remaining – grid codes).
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59. Eye on Arxiv: Quantum corrections to eta/s
I decided to turn the de Sitter discussion off for a moment, it would be more appropriate to return to it after the paper is ready anyway 
Hopefully, it will not take too much time for you to see it in ArXives.
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58. Stability of de Sitter space: dS as a perfect interferometer
Let us now show that QFT of a massive scalar field in de Sitter space features instabilities if the number of dimensions is odd. The expression for the two-point function found in the previous post will be of no help, so we will have to switch to the language of Bogolyuov coefficients and modes.
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57. Stability of de Sitter space: statement of the problem 1
Ok, friends, I feel that the time has come to let you know about things I am currently involved in – namely, understanding of intrinsic stability of the de Sitter space.
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51. Planck 2008: day 4 – Soft wall AdS/QCD
I discuss the soft wall AdS/QCD model introduced by Batell&Gherghetta, where AdS gravity and dilaton behavior providing soft wall cutoff is introduced self-consistently.
38. And again about effective QFT for inflation
I show that effective QFT corrections to correlator of Mukhanov variable found by Armedariz-Picon et al. are due to effects of eternal inflation.
37. Eye on PRL – On statistical theory of developed turbulence
I discuss developed turbulence a bit: dynamics of vorticity in the inertial interval and Kolmogorov cascade.
36. Eye on ArXiv: 6 May 2008 – Where does the cosmological perturbation theory actually break down?
I discuss the issue of cosmological perturbation theory breakdown and its relation to the regime of eternal inflation
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