LHC first collisions at 7TeV (CoM)

March 30, 2010

Today we witnessed the first collision events at the Large Hadron Collider at 7 TeV (centre of mass energy). The build-up started at around 6am European Time when they started the first attempt to ramp the energy of the beams up to 3.5 TeV. In fact it was not until the third attempt that they finally got the beams up to the required energy and saw the first events at 1pm.

In case you missed it, here is a recording of the webcast from CERN at the crucial moment.

Here is what a 7TeV event looks like in the LHCb experiment

If you still have not has enough here is another video of the occasion from the ATLAS control room.

If that’s too much, be grateful. I recorded about 30 hours of video stream and these are the exciting parts.

Abel Prize for Mathematics

March 24, 2010

The Abel Prize in mathematics for 2010 has been awarded to John Torrence Tate for his work in number theory.

Tate is known for his work on automorphic forms, L-functions and elliptic curves. He had previously been awarded the Wolf prize in 2002

Vote for your choice of FQXi essay contest topic!

March 23, 2010

The Foundational Questions Institute is gearing up to launch its third essay contest, and this year they are holding a vote on what the subject of the essay should be. The topics for the previous two years were “The Nature of Time” and “What is Ultimately Possible in Physics?” The great thing about this contest is that it is open to everyone. The FQXi are one of the few organisations that accept submissions as freely as viXra.org does, so many people who use this archive will also be interested in this contest.

Even better is that the last two years have seen essay submissions from amateur and professional scientists alike, so it is a wonderful David and Goliath fight. So far the score is 2-0 to Goliath but I think the organisers genuinely want to see some outsiders win something, so anything is possible. Even if you don’t win you will have the opportunity to discuss your essay and other people’s work on the same subject in the FQXi forums prior to judgment day. That is more valuable for many people than the potential prizes.

So if you are interested go over to the voting page now and have your say on the essay topic. You can vote for any combination of the 10 possible questions and you can only vote once. This means that the information content of your vote is maximised by selecting exactly 5 of them. Whether you are a David or a Goliath you should feel encouraged to vote and to enter the contest once it is announced.

“crackpots” who were right 4: Ignaz Semmelweis

March 23, 2010

Like many people these days I have experienced the thrill of tracing my ancestors using some of the online resources and public archives available. In my case a large number of my ancestors that I can trace lived in Victorian London and in following their lines I am struck by the high mortality rates, especially among children and mothers in childbirth. It is particularly sad to learn that a significant number of those deaths could have been prevented if medical practitioners had paid attention to the work of  Ignaz Philipp Semmelweis. That makes this entry in our series about “crackpots” who were right the most shocking case that I am aware of.

Medical knowledge in the early 19th century was very limited. The theory of diseases spread by germs was not understood until after the work of Louis Pasteur from 1864 and effective treatments for infections were not available until the discovery of the medicinal effects of penicillin much later. The leading theory of diseases was dyscrasia based on the ideas of an imbalance of the basic “four humours” and the usual treatment was bloodletting or extreme forms of hydrotherapy which often did more harm than good. It was thought that disease was spread by bad air until the 1854 Broad Street cholera outbreak when John Snow identified contaminated water as the source of the cotangent. Such advances dramatically improved the prevention of diseases, but an earlier discovery could have saved many more lives in London and other cities if it had been accepted more widely.

In 1847 Ignaz Semmelwies was a physician working at an obstetrical clinic of the Vienna General Hospital where his duties included inspections, teaching, supervision of difficult cases and record keeping. When he took on his responsibilities the clinic had a particularly bad record for maternal mortality due to puerperal fever which was causing the death of 10% of new mothers. A second clinic had a better rate of only 4% so women would beg to be admitted there instead. The situation was so bad that many would prefer to give birth at home with no medical supervision and indeed the survival rates were probably better under such circumstances. Naturally Semmelweis was not happy with this situation and he set about looking for the cause by carefully eliminating possibilities and keeping the best possible records of all cases. He soon found that the cause of the problem was related to cleanliness so he instructed the doctors and midwives to wash their hands with chlorinated lime solutions which were most effective at removing smells. The result was a dramatic ten fold decrease in mortality rates.

News of the breakthrough spread round Europe via lectures and reports delivered by students of Semmelwies. Given the clear evidence for the effectiveness of the washing procedure and its easy reproducibility you might expect that it would have been adopted quickly. But sadly there was considerable resistence and only a few hospitals in Germany followed the practice. As a result it can be estimated that some tens of thousands of mothers died needlessly following child birth.

In part the problem was that Semmelweis offered no explanation for why his procedure worked. It was a purely empirical observation that could not be explained until the theory of germs became current some twenty years later. At the time doctors believed that such deaths had numerous causes because autopsies seemed to show significant variations of the decease. Reactions to Semmelweis were very mixed. In England doctors thought that the fever was contagious and they mistakenly took the new result as simply a confirmation of this theory with nothing new to report. In part the fault lay with Semmelweis himself because he did not publish an explanation of his results himself and information passed secondhand via his students. Nevertheless it is clear that the failure to change hygiene practices was not just through misunderstanding. There was considerable resistence, not least because the egos of the top physicians of the time would not allow them to accept that their own uncleanliness could be a cause of disease. In 1956 Jozsef Fleisher, an assistant to Semmelweis reported supporting evidence from another clinic in the Viennese medical Weekly. The editor remarked sarcastically that it was time people stopped being misled about the theory of chlorine washings. Such reactions were not atypical. Semmelweis’s doctrine was finally rejected at a conference of german doctors which included the celebrated Rudolf Virchow who was considered a scientist of the highest authority at the time. It was the ultimate blow from which Semmelweis could not recover.

In 1861 Semmelwies’s apparently suffered a breakdown through depression. He would turn every conversation to the topic of childbed fever. By 1965 he was considered an embarrassment to his colleagues and was tricked into entering an asylum where he was held in a straightjacket against his will. His bad treatment there led to his death from gangrene that year and his work was conveniently forgotten. Some people speculate that he may have suffered from Alzheimer’s, bipolar disorder or some other mental ailment we recognise today. But consider this. He knew that each day mothers were dying needlessly at the moment that should have been their families greatest joy. It was an unnecessary tragedy perpetuated by the arrogance of doctors and could be stopped if only people would listen to him. Through his work in his own clinic he would have seen first hand the hurt that this caused. He was unwilling to accept that, and they called it madness.

XtraNormal Physics

March 20, 2010

I see that Sean Carrol over at the Cosmic Variance blog has discovered XtraNormal animations. Here is a short video he posted.

Not bad Sean! For those who did not see it before here is a version of the stringwars video I did a little while ago.

This was an attempt to highlight how ridiculous the “string wars” are. String Theory and Loop Quantum Gravity really do have common origins and common features that should suggest they can build on each others strengths, yet the theorists just criticise each other instead of trying to work together. I wonder how people will look back on this era when more is known.

Making XtraNormal videos is very easy and great fun so if you have some time to spare go and see what points you can make with the laconic humor at http://xtranormal.com/ If you come up with anything science related you can share it here by adding a comment with a link.

3.5TeV beams circulate at LHC

March 19, 2010

There is great news from CERN this morning with word that beams have beam accelerated to 3.5TeV, three times the highest accellerator energies ever seen before. This is the energy that the LHC will run at this year. It will be a huge relief to everyone because until this point nobody could be really sure that the magnets could take the required current of 6000A without a drastic failure like the one seen in 2008.  For the next two weeks or so they will be performing further tests including the first collisions this year at 450 GeV. There will also be runs with 4 on 4 bunches which are required so that all the experiments can see collisions at the same time. Then on 30th March they will perform the first collisions at 3.5TeV and that will signal the start of real science at the LHC. For further reports around the blogosphere try Cosmic Variance and Not Even Wrong.

Meanwhile the Atlas collaboration have posted their first paper using data from last years collisions at 900 GeV. For details on that you want The Collider Blog

“crackpots” who were right 3: Ernst Stückelberg

March 17, 2010

Baron Ernst Carl Gerlach Stückelberg was one of the most accomplished theoretical physicists of the middle twentieth century. He ranked alongside such greats as Feynman, Dirac and Fermi, but you could be forgiven for not knowing it. His name appears in physics text books only when attached to some relatively minor phenomena such as the Stückelberg mechanism. Even in popular physics books that recount the glorious history of that golden age of discovery in physics, he is rarely mentioned. Yet Stückelberg made prior breakthroughs in at least three developments that led to Nobel prizes for others, and he contributed to a wide range of other research topics in particle physics and quantum theory. 

Here is a short list of some of his greatest achievements (taken from Wikipedia)

  • 1934: He devised a fully covariant perturbation theory for quantum fields that was more powerful than other formulations of the time.
  • 1935: He gave vector boson (meson) exchange as the theoretical explanation of the strong nuclear force. This is normally credited to Yukawa who discovered it independently at around the same time, and who was awarded the Nobel Prize.
  • 1938: He recognized that massive electrodynamics contains a hidden scalar, and formulated an affine version of what would become known as the Abelian Higgs mechanism.
  • 1938: He proposed the law of conservation of baryon number.
  • 1941: He presented the evolution parameter theory that is the basis for recent work in relativistic dynamics
  • 1942: He proposed the interpretation of the positron as a negative energy electron traveling backward in time, an observation often attributed to Feynman.
  • 1943: He came up with a renormalization program to attack the problems of infinities in quantum electrodynamics (QED). This was a precursor to the fully renormalized theory of QED completed in the 1940s which netted a Nobel prize for Feynman, Schwinger and Tomonaga.
  • 1953: He and Andre Petermann discovered the renormalization group, but it was Kenneth Wilson who took the Nobel Prize for work that demonstrated its full worth in critical phenomena. 

So why is Stückelberg not more widely recognised for these achievements? There seems to have been a number of factors at work. Firstly he had some bad luck with publications. He did not publish his work on the meson simply because Pauli said it was ridiculous. His work on the renormalization program was rejected by the Physical Review who said it was more of a program outline than a paper. Sadly no copy of this work was preserved. He is said to have gone on to develop a full theory of QED by 1945 which is recorded in the thesis of one of his students but the credit went to others.

Another element may have been his isolation in Switzerland before and during the war when he did some of his best work. However this seems unconvincing when you consider that he established good friendships with other well-known physicists of the time. He could be considered less isolated than physicists working in Japan such as Tomonaga whose work on QED was recognised later. One other contributing factor that is given part blame for his lack of credit is that he invented unusual notation for his work that made it difficult to read.

Whatever the cause, he ended his life feeling lonely and rejected. When Feynman gave a lecture in Switzerland in 1965 he spotted Stückelberg after the lecture leaving quietly from the back. Pointing to Stückelberg, Feynman remarked “He did the work and walks alone toward the sunset; and, here I am, covered in all the glory, which rightfully should be his!”

The story of Stückelberg shows just how easy it is to be overlooked in science. There is no convincing reason why he was not given the full credit he deserved for his work, but it would have helped if he had presented his work more clearly and fully. While people like Feynman gave seminars and wrote books, Stückelberg seems to have quietly accepted his rejections and left it to others to speak up for him. But that was something they did not do enough. There is a lesson to be learnt here. Most of us cannot claim achievements comparable to those of Stückelberg so if he can be overlooked the rest of us should take nothing for granted. It does no good to make a discovery and bury it so deep that nobody pays any attention until it is rediscovered by someone else who is better at presenting it. Research needs to be explained clearly and publicly or it sinks into obscurity.