Back to work

24/08/2009

Today I am back in my office and physics, that I never stopped to think of, is unfriendly urging in my mind. Besides my work as a reviewer for Mathematical Reviews that I try to do at my best, I have not forgotten to look around in the blogosphere. In these days there is a lot of fuss about a recent paper by Fermi Collaboration (see here). You can find some discussion here but it is not the only blog discussing this matter: An inflamed discussion is also here. Is loop quantum gravity dead? I can only spend a few words here by saying that is really too early to draw such conclusions but the results from Fermi Collaboration are really beautiful and open the premises for a bright future in the observation of gamma ray bursts. I would like to remember here the point of view of Steven Weinberg claiming that we finally hit exact truths on Nature (the bitch not the journal as  Tommaso Dorigo uses to say ). These truths are special relativity and quantum mechanics. I share this idea and the more beautiful idea that we are indeed able to reach such exact truths, the same mathematicians are able to achieve. On the same ground, if some experiment should come out claiming that these theories should be modified, I would be glad for one thing: A great opportunity for my generation to put hands on a deeper truth.

I am still working on a perturbation analysis of a non-perturbative Higgs field interacting with a fermion. I am solving Heisenberg equations of motion with a very large coupling for the Higgs. I hope to get some further time to complete the computations that may become really involved.

About QCD there is few to say. I have got my paper accepted for publication as you may know that implied a nice correspondence with Terry Tao. We can say that, after the very good Terry’s intervention, the proof of the mapping theorem is indeed complete. Another paper hit my interest and arose from a Japanese group working on lattice (see here). I have had an email exachange with Hideo Suganuma and surely their results are something to think about in depth. I hope to see other papers in the near future as this area of physics is very active indeed.

Finally, great expectations are for LHC. It will start on November and we hope to see results very soon. Infancy problems should be overcome and it is time to see the face of Higgs (the particle not the professor). Good luck, folks!


QuAD constrains parity violation on a cosmic scale

22/04/2009

QuAD is a collaboration that involves several institutions that aims to measure polarization of photons of the Cosmic Microwave Background radiation that is the relic radiation that started to freely propagating in the universe 400000 years after big bang. QuAD aerialThis radiation is a precious source of information for a deeper understanding of the birth of our universe and a fundamental test-bed for our theories. This collaboration proved that our “standard model” of the universe again agrees with their measurement about polarization of this radiation. But, from these data, physicists are able to get something more. In a paper appeared in the last number of PRL (see here and here), they showed that electrodynamic forces are proved to not violate parity on a cosmic scale and, last but not least, interactions that violate Lorentz invariance are strongly constrained.

I should say that this is an important conclusion to be drawn from an elegant experiment and an unexpected source.


Evidence for dark matter from PAMELA

02/04/2009

Two lines to point out this paper, appeared in the latest number of Nature, coming from PAMELA Collaboration. This project is directed by Piergiorgio Picozza. He has been my professor of nuclear physics at Rome University La Sapienza (but all my mistakes about are my own responsability…). pamelaPAMELA is a satellite that is orbiting Earth since 1023 days to date (you can find a counter on PAMELA’s site) and is gathering data about cosmic radiation. They have found an enhanced production of positrons. In this last paper they reach the relevant conclusion that this excess may come from dark matter through an annihilation process. This appears a significant evidence for the existence of this exotic matter that we expect to be produced at LHC in the next months as the consequences of the accident happened last year will be definitively fixed. Let me say that I find PAMELA exceedingly sexy as what she is saying to us is really exciting.


Most extreme gamma-ray blast yet

20/02/2009

As my blog’s readers know, I follow as far as I can space missions that can have a deep impact on our knowledge of universe. Most of them are from NASA. One of these missions is Fermi-GLAST that has produced a beautiful result quite recently.  glastIt has seen the greatest gamma-ray burst ever (see here). The paper with the results is appeared on Science (see here). The burst was seen in Carina constellation.  These explosions are the most energetic processes in the universe and were uncovered by chance with military satellites named Vela used to find nuclear explosions in the atmosphere in the sixties of the last century. Understanding gamma-ray bursts implies a deeper understanding of stellar explosions.


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