CERN is waking up slowly, but it'll take a while till something starts happening. I can use this time to recall my favourite bits of 2007. Like every year, the past year arXiv papers that I enjoyed the most are awarded the prestigious Narrow Resonaance awards. This year's Narrow Resonaances go to (drums) :
1. G.Dvali, S.Hofmann, J.Khoury,
Degravitation of the cosmological constant and graviton width,
I wrote about it the other day. The idea is to solve the cosmological constant problem by modifying gravity at long distances such that large wavelength sources, like the cosmological constant, are effectively filtered out. A complete, non-linear model that could achieve it does not exist yet. Gia et al. just propose a phenomenological description of massive or resonance gravity theories with the desired long distance behaviour.
2. E.Katz, T.Okui,
The 't Hooft Model As A Hologram,
AdS/CFT is still a mystery mainly because, typically, we can calculate on the weakly coupled side only. For some toy models, however, the strongly coupled side can be solvable too, so that we could explicitly see how the AdS/CFT prescription arises. This paper maps 2D QCD at large N to 3D AdS gravity and relates the parton-x variable in QCD to the radial coordinate in AdS3.
The two previous papers have 3 citations (together), but I could not quite ignore the most cited paper of 2007. I had my doubts though, mainly because of the lemming rush that followed. The bulk of these unpapers could well have the abstract: ''We consider unparticles in whatever uncontext. You are encouraged to forget the paper as soon as soon as you add it to your citation list". Moreover, two recent papers, here and here, point out that an explicit construction of the conformal sector typically leads to a different phenomenology. Nevertheless, I must give the credit to Howard for drawing our attention to a whole wide class of collider signatures. Besides, I appreciate Howard's writing style. He is probably the last man on Earth who truly enjoys particle physics.
Consolation Bump goes to
S.Dubovsky, A.Nicolis, E.Trincherini, G.Villadoro,
Microcausality in Curved Space-Time
A little neat thing about quantum field theory in curved backgrounds. They show that causality of the classical theory implies micro-causality of the quantum theory. Clear and illuminating.