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Archive for March, 2009

Meeting informally with colleagues working on slightly different topics always bears a certain danger: You might actually get drafted to give a talk on one of the things you are working on, often on very short notice. This is what happened to me Wednesday night, at the monthly informal get-together of the members of the Excellence Cluster ‘Universe’, a newly established research center focusing on nuclear, particle, astro-particle and astro physics. More about this, and my role in the Cluster, in a later post.

Oleg Andreev, a theory fellow at the Cluster working on string theory, is organizing a journal club / informal seminar, and he needed a speaker for Friday morning. He asked me to speak about the International Linear Collider ILC, and would not accept my more or less lame attempts at excuses. So, with about 36 hours left and a lot of other critical things still to do, I started to prepare a presentation on the ILC for a diverse audience, mostly to introduce the concept of this proposed machine. But beyond the stress and extra work, such things are always opportunities to contemplate the bigger picture of what I’m working on.

My focus is the development of detectors for this future machine, but first lets start of with a very brief introduction of what this project is about. The ILC is being discussed as the next big project in high energy particle physics, and will complement the Large Hadron Collider LHC at CERN, that will hopefully deliver its first physics results later this year. While both these science projects aim at discoveries beyond the by now well established Standard Model, they follow different strategies. The LHC, with its high energy (14 TeV in the proton-proton center of mass), is a true discovery machine which opens up new horizons for particle physics. Compared to this energy, the ILC seems rather modest, with initially only 500 GeV (0.5 TeV). However, it will collide electrons and positrons, not protons. Since these are elementary and not composite particles, the full energy is available in the particle collision, and not only a small fraction of it as in the case of the LHC. Also, because of this, the events (that is what we call a “picture” of a collision that is recorded by our detectors) at the ILC will be much cleaner, allowing studies with much higher precision than at the LHC. Together, these machines unfold their full potential, combining energy reach and precision. I am convinced that the interplay of these two colliders will be crucial to establish a new map of the landscape of particle physics beyond our current understanding. The precision measurements at the ILC are only possible with new detector technologies, and this is where my work comes in… to be elaborated on later.

The use of electrons at the ILC brings its own set of challenges, however. Maybe the most striking one is that you can not build it as a circular storage ring like the LHC. The reason for this is the energy loss of charged particles when they travel on a curved path, which increases with decreasing mass of the particle, but to the 4th power. So an electron will lose more than 10 trillion times more energy than a proton on the same path at the same energy, since it is about 2000 times lighter. This kills the beautiful and extremely successful storage ring concept for high energy electron colliders, and is reflected in the name “International Linear Collider”. So, the next generation electron-positron collider will be a long, straight line, accelerating electrons and positrons from oposite ends and colliding them in the middle. Here is a sketch of what it might look like:

Schematic layout of the proposed International Linear Collider.

Schematic layout of the proposed International Linear Collider.

One of the key things here is to get the electrons accelerated as quickly as possible, to keep the machine as short (and thus as cheap) as possible. This requires high acceleration gradients, an interesting topic for a future post. With the presently available technology, the ILC is about 30 km long. This is where the “International” in the name comes in: A project of that size can only be realized as a world-wide enterprise. This is a universal feature of projects at the energy frontier of particle physics, and for me also one of the attractions of the field. Working together across continents and across different cultures and time zones is thus part of the everyday live of particle physicists, something I don’t want to miss.

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Italy visit in March

Tuesday, March 31st, 2009

Quantum Diaries starts again. At its first start in 2005, my friend Zhizhong Xing, a neutrino theorist, contributed a lot of interesting articles. After the Quantum Diaries paused, Zhizhong moves to a Chinese scientists’ blog site, http://www.sciencenet.cn/u/xingzz, keep spreading all kinds of fancy news.

It is said that this restart is more or less motivated by the upcoming release of the movie “Angels and Demons”. I am very impressed by this novel. “Angles and Demons” is written by Dan Brown. A physicist at CERN created anti-matter, which could be used as a MDW (Mass Destruction Weapon), which we failed to search out in Iraq. The anti-matter was stolen and hidden in Vatican to threaten the on-going Pope election. When I heard the news that Quantum Diaries will be restarted, I am preparing for a workshop in Venice, Italy, Neutrino Telescope 2009. Last time I visited Italy was in 2005, soon after I read this novel. I went to Frascatti in suburb of Roma for the Neutrino Factory Workshop. I have been in Roma once in 2000, as a tourist. But I haven’t any impression on the metaphor of the buildings described in Dan’s novel. After the meeting, I came to Roma in the early morning by train. My flight was in the evening. I had one day to investigate these great buildings. The left-baggage office at the train station was crowded incredibly with a 2-hour long queue. Thus I had a very special experience, with a backpack and a luggage, walking along the route in Dan’s novel, up to the Castle Santa Angelo.

Back to the Venice meeting. Venice in March is very beautiful. Italian food and wine are excellent. Of course, the talks and discussions are identically interesting. For example, Prof. Minakata from Tokyo Metropolitan University gave a talk titled “Neutrino non-standard Interactions: Another eel under a willow?”. Actually he means “another loach under a willow”, a Japanese proverb. Loaches like to live under willow trees. This proverb means that just because you caught a loach under the willow tree once, it doesn’t necessarily mean that there will always be a loach there. He asked the audience if they know loach. I am surprised that nobody responded yes. Probably that’s why Minakata San changed the loach to eel. I am no longer a theorist for long time, thus have difficulties to catch point from a bunch of formula in this talk. But I know loach very well. It is common in rice-planting area. Well, there is a famous Chinese dish, called loach in Tofu.

量子日记又重新跟大家见面了。2005年量子日记启动的时候,我的朋友、中微子理论家邢志忠教授曾为大家贡献了不少有趣的文章。量子日记暂停后,志忠又转战科学网博客,坚持不懈,孜孜不倦地提供各种小道消息。

据说这次重新启动与《天使与魔鬼》电影5月15日公映活动有关。《天使与魔鬼》是丹•布朗写的小说,《达•芬奇密码》的姊妹篇。小说的背景是欧洲核子研究中心的科学家维特勒研制出了蕴含着极其强大能量的反物质,结果被人杀害,反物质被人窃取,藏到了梵帝冈,用以要挟即将进行的教皇选举。接到量子日记重新启动的消息的时候,我正在准备去意大利参加“中微子望远镜2009”研讨会。上一次去意大利是2005年,我刚看完《天使与魔鬼》不久,到罗马郊区的Frascatti参加“中微子工厂”研讨会。2000年时候,我曾经到罗马走马观花地旅游过一次,但对书中建筑的种种隐喻完全没有印象。开完会后,第二天清晨坐火车来到罗马。飞机要很晚才起飞,我有将近一天的时间重新看一看。罗马火车站行李寄存处生意兴隆,排了至少两小时的长龙。于是我背着包,拖着行李箱,沿着丹•布朗的路线,一直走到天使堡。

威尼斯的三月非常漂亮,意大利饭和红酒非常好,当然,会议报告也同样有意思。例如,来自东京都立大学的Minakata教授做了一个报告叫“中微子非标准相互作用:柳树下的又一条鳗鱼?”。出处来自日本的一条谚语“柳树下的又一条泥鳅”。泥鳅据说喜欢呆在柳树下,你曾经在柳树下找到了一条泥鳅,但并不意味着在同一个地方还能抓到一条。他问“你们知道泥鳅吗?”,与会的大部分西方人没有反应。我想这也是他题目中把泥鳅改成鳗鱼的原因。我已长久不关心理论物理,因此无法在报告内容的一大堆符号中抓住关键。不过我很熟悉泥鳅,它在适宜种植水稻的水乡是非常常见的。还有一道名菜叫“泥鳅豆腐”。

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Music of the Spheres

Tuesday, March 31st, 2009

A quick thought on the parallels between physics, and my other love, music. I have always considered myself a musician, although I am not as proficient as I’d like to be. There is a stereotype that physicists only listen to classical music, perhaps due to the appreciation of the underlying mathematical constructs, but although I am a huge classical fan, I was brought up with my Father’s vinyl collection: The Doors, The Beatles, Jimi Hendrix, Bowie, Dylan,… This has highly influenced the kind of music I appreciate today.
The main thing I wanted to share however, was an exchange I had with one of my closest friends who is a Jordanian composer, currently working on a theatrical production to celebrate the initiation of the ancient city of Petra into the ‘seven wonders of the world’. We often have lengthy conversations over some single malt about physics, and for a musician, the guy has an impressive collection of popular science tomes. In an email exchange recently, I posed to him a thought I’d had in reaction to some ‘anti-scientific’ exchanges I’d had on Youtube with a supporter of Creationism along the lines that ‘science destroys the beauty of nature’. Here is my email excerpt to my friend (excuse the maloquence!):

Recently I was debating with someone about scientific reductionism. Their argument was that science somehow belittles the beauty of nature because it seeks to understand reality in its microscopic and most fundamental form by the breaking down of its description into mathematics and laws etc. They argued that the beauty in life is in the mystery, in the not knowing, and that was the basis for a lot of the feeling of people with ‘faith’. I tried to argue back that science is not ‘reducing’ nature by understanding it, and in fact most scientists see beauty in nature and reality in the same way, if not stronger, than most people. 
Then I thought about the example of music. When you first hear an amazing song, you experience it totally and freely and let the sounds sink into your ‘soul’, but then we, as musicians, feel compelled to listen deeper, to understand just how the guitarist hit that pinch harmonic or bent that note a fraction of a second later than we’d expect, of how there are probably three, not two, keyboard tracks laid on top of one another and they’re just out of phase and recorded at different locations relative to the mics giving a certain ethereal dimension. Then we pick up the guitar and we try to mimic the music, and we take it and we make it our own, and we sing it to ourselves and maybe even perform it to others, but do we now think that the music is less beautiful because we have taken away the mystery? Do we appreciate it less because we understand the sound waves and the admixtures and exactly what we’d need to reproduce it? I don’t think so, because if true, then all musicians would be incapable of enjoying music, because every time they learned a song it would become banal, and they would lose their passion, but the passion stays, and that is what drives musicians, and also scientists, because there is always joy in understanding, and always another puzzle to solve. And physics is exactly that – it is the learning of the song of nature, with a mind to being able to perform it ourselves, and reproduce its notes, that we might discover other songs and other dimensions of melody not yet conceived. 
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Is there a prize for being the last blogger on the new Quantum Diaries to get started? Do I win? If my former thesis adviser is lurking out there, he will tell all within earshot, with a Scottish accent, softened only a little by years in Toronto, “You expected him to be on time? Why would he start now?”

So what I am up to? Last fall I joined with a group of other scientists working to develop a new experiment, named Mu2e, that we propose to build at Fermilab, a High Energy Physics lab just outside of Chicago. Fermilab is, today, on the cusp of a great transition; for about the past 20 years Fermilab’s Tevatron storage ring has worn the crown of the world’s highest energy colliding beam accelerator, a crown that will soon pass to the Large Hadron Collider (LHC) at CERN. Many of us at Fermilab seek to reinvent the lab for the post-Tevatron era and I will tell you about my part of that effort. Some of the other bloggers will talk about their efforts; Dave Schmitz already has one post on his experiment.

Our quest, is to look for a very rare decay of an elementary particle named a muon. Why are we doing this? It’s the quantum mechanical equivalent of taking the short-cut through the woods to Grandma’s house. The enormous body of data acquired by high energy physicists over the past 50 or so years suggests that new subatomic particles lie at the brink of discovery. Why have we not yet seen them? The most likely answer is that their masses are too high. One way to look for high mass particles is to build the mother of all accelerators, one with a high enough energy to produce the new particles directly. That was, for many years, the role of the Tevatron and it will soon be the role of the LHC. Another way to look for these particles is to exploit quantum mechanics, which tells us that very massive particles can make small changes to processes that take place at much lower energies. The magic words are virtual particles and loop diagrams; I have no idea how to make those words mean anything without giving the whole course. The most powerful such search is to look for a process that is forbidden, or almost forbidden, by physics we already understand; in such a case any signal at all is the sign of something new. That is the quantum mechanical short-cut through the woods: if physics breaks the right way, we can compete with the largest, highest energy accelerators by making very careful measurements using tools we already have.

That’s not to say it will be easy. When we traded away the need for very high energies, we received, in return, the need for exquisite understanding of our backgrounds. More on that another day. And I will find some drawings to add.

And one final comment, a followup on what Chris Ruiz and Anadi Canepa had to say about Vancouver. I spent much of two summers working at TRIUMF, a lab on the campus of the university of British Columbia. I have yet to solve the following mystery: is Vancouver, running away, the coolest city on the planet or would I have thought the same of whichever city in which I happened to spend the summers that I was 21 and 22?

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The Nuclear Burden

Monday, March 30th, 2009

I had hoped to write about the nature of physics colloquia and how they vary from place to place, but instead, I’d like to write about the topic covered by today’s SLAC colloquium: Sidney Drell presented “Rekindling the Vision of President Reagan and General Secretary Gorbachev at Reykjavik: Steps Toward a World Free of Nuclear Weapons.” Sidney Drell is one of many accomplished physicists who have also done work regarding policy and nuclear weapons. The late SLAC Director Emeritus W. K. H. Panofsky is another.

Drell focused on the plan at the Reykjavik meeting in 1986 for complete nuclear disarmament (see ‘Reykjavik Summit: The Legacy and a Lesson for the Future’ for more). While it didn’t work, it was a first step towards a reduction in nuclear arms that has occurred. Recently, conferences were organized to revisit the original goal of complete disarmament. The experts gathered authored recommendations that were published in 2007 (“A World Free of Nuclear Weapons,” Wall Street Journal) and 2008 (“Toward a Nuclear-Free World”, Wall Street Journal).

Half a century ago, many physicists were coping with the weapon that had been developed from their labor. The cold war triggered further policy work by physicists and brought the consequences of the atomic bomb to the populace, who were trained to “duck and cover.” The world has changed, both for physicists and the general public. I’m 24 – I don’t remember the Berlin Wall falling, and never had nuclear drills in school. As an American, I fear unattended luggage in airports more than a nuclear attack. As a physicist, the Manhattan project feels like a part of distant history, like the development of quantum mechanics or relativity.

Listening to Sidney Drell’s talk today made the nuclear threat much more real. While there is a risk of a mistake involving the management of nuclear weapons (like a bomber accidentally carrying warheads over the US), Drell believes there is a greater risk of terrorists gaining control. Disarmament is still as important as ever, yet the US has been slow to ratify and sign nuclear treaties. START expires this December, which was responsible for removing 80% of strategic nuclear weapons. Should my generation care? Of course. As voters and citizens, we can influence our leaders to prioritize disarmament, rather than believe this is only a concern of the past.

Finally, we have the responsibility to learn from our mistakes. Those of us who did not live during the bombings of Nagasaki and Hiroshima or witness the cold war should still fear a future occurrence of these events. Drell and others have written many books on the development, use, and cold war legacy of the atomic bomb. One book stands out to me, Atomic Energy for Military Purposes by Henry Smyth, from 1945. It is a technical, dry book written about the Manhattan project before the Trinity test. Very little was unclassified at the time, but the book hoped to explain the project to a technical audience. As physicists, we have a lot to learn from this book. It shows how the scientists understood and justified the work they were doing, even before they witnessed the atomic blast. We should keep these lessons in mind during the development of future technologies.

The final chapter breaks from the formal tone and is a plea for the reader to understand – and take action regarding – the project. The final section, “The Questions before the People”, beautifully expresses the relationship between this new weapon, the scientists who created it, and the public as a whole:

Here is a new tool for mankind, a tool of unimaginable destructive power. Its development raises many questions … Because of the restrictions of military security there has been no chance for the Congress or the people to debate such questions. They have been seriously considered by all concerned and vigorously debated among the scientists, and the conclusions reached have been passed along to the highest authorities. These questions are not technical questions; they are political and social questions, and the answers given to them may affect all mankind for generations … In a free country like ours, such questions should be debated by the people and decisions must be made by the people through their representatives… The people of the country must be informed if they are to discharge their responsibilities wisely.

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Weekend Musings

Monday, March 30th, 2009

Echoing something I’ve read on a few of the other blogs in Quantum Diaries, I want to expand on the sentiment that ‘physicists need to relax too’, because…well, relaxing is a subject close to my heart! 

The walk to work

The walk to work

 I’ve just spent the weekend on the beautiful Vancouver Island, in its main city of Victoria, which is, incidentally, the capital of the Province of British Columbia and the seat of the parliament here.
An old colonial town, full of very British architecture and some great seafood joints, Victoria is not considered as trendy and modern as Vancouver, something that has led it to be given the moniker ‘Home of the newly-wed and the nearly-dead’!. Nevertheless, I find Victoria an extremely tranquil, relaxing, and rejuvenating place to visit. The weather this past Sunday was gorgeous – the bright spring sunshine warm enough for a leisurely cycle along one of Victoria’s many hidden cycle routes passing through farmers fields, vegetated and rocky walled embankments and protected marshland over extensive boardwalks.
Despite having the luxury of a job that drives me and instills passion in me, I am a true believer in leaving work behind at the weekends. I consider myself very lucky to be able to practice physics in one of the best laboratories in the world, which resides in such a beautiful part of the world in terms of geography and standard of living.
Vancouver, and the ‘lower mainland’ of British Columbia, suffer from a delectably mild climate. I say suffer only because I am quite fond every now and then of a great storm, crashing waves, beating hail, a ten-day blizzard, gale-force winds etc, which Vancouver has none of, but I say delectable because the predictability and beauty of Vancouver’s winter and summer weather allows a steady calendar of extra-curricular activities to be planned. In the winter, there is skiing and snowboarding; either on the local mountains (Cypress, Seymour and Grouse) or up in the famous resort of Whistler. On a clear sunny day on top of Cypress mountain, only 40 minutes from my door, you can be up to your knees in fine powder snow while the sprawling view below you of the city, its beaches, and the Straight of Georgia takes your breath away.

 

The vista from Whistler Peak

The vista from Whistler Peak

In the spring, it rains. That’s about it. It can rain for 20 days at a stretch, and basically you’d better own some good rain gear because it is the most annoying kind of rain that I have encountered: the kind that is so fine that it permeates everything and you can find yourself soaked within minutes. At least it is not as bad a trying to walk in Edinburgh Scotland, my hometown, on a windy, rainy day. I think it was Billy Connolly who said something along the lines that in Scotland the rain and the wind combine so as to appear that the rain comes up at you from the ground, so that bending over won’t do you any good.
The summers in Vancouver are gorgeous. It doesn’t get hot like in the Mediterranean, but it is usually hot enough that every day requires the wearing of shorts and t-shirts, and Vancouver residents are quite hardy – only abandoning such gear when the weather really deteriorates. The beaches are a great place to find people playing drums, strumming guitar, and illegally drinking beer and having barbecues – yes, I know, it is so barbaric that two of the most basic signs of civilization, alcohol and fire, are banned in public here!

 
The climate in Vancouver is officially cast as an oceanic climate I believe, and the coast is covered in most places by a thick coniferous rainforest, apart from some of the warmer Gulf Islands where beautiful Arbutus trees can be found hugging the water’s edge, their boughs evocative of the feminine form and showcasing their beautiful, multi-hued peeling bark. Some of the most primal and gigantic old-growth rainforest can be found here, and I would recommend anyone who travels to this region to explore the northwest coast of Vancouver Island, which certainly left me with a great impression.
TRIUMF has the lovely advantage of being stuck whack on the edge of the Pacific Spirit Regional Park – a protected area home to a myriad of wildlife and an absolutely beautiful way to walk to work early on a summers morning when the sun is just beginning to stream through the thick canopy. Although surrounded by major roads on all sides, and a busy University Campus (UBC), the silence afforded by the trees is uncanny – I really do love walking to work that way – if only my 17” laptop weren’t so heavy! Next time I’ll buy one of those miniature ones I think ☺

 

ISAC II Entrance, TRIUMF

ISAC II Entrance, TRIUMF

I have included some pictures from Vancouver in this post. Of the mountains in winter (view from Whistler peak looking towards Vancouver) and the forest near TRIUMF in summer.
Please come and visit this beautiful place if you ever get the chance.

Kits Beach - Vancouver

Kits Beach - Vancouver

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Quantification

Monday, March 30th, 2009

Hi, Tony. Thank you very much for your comment for ‘Japan on the globe’. Yes, surely we should remember the effects from ancient Greeks and ancient Egypt, so on. Here I would like to say physics consists of two steps;

  1. Quantify the phenomena and book numbers.
  2. Analyze the structure behind numbers.
Ticho Brahe's notebook

Tycho Brahe's notebook

In the 16th cent., Tycho Brahe accumulated the data on movement of Mars for 16 years!! Then with this data, Johannes Kepler got ‘Kepler’s Three Laws of Planetary Motion’.

Kepler’s insight from data to the laws was marvelous which led the theory of gravity of Newton. But I am also quite interested in quantification of Tycho. The accuracy of his data were within 1 arc-minute if referred by fixed stars, within 2 arc-minute in usual and within 4 arc-minute on the location of planets. It was so accurate when compared with the case of Copernicus, who was satisfied if his theory agreed with data in 10 arc-minute.

European seems to have tradition to respect to accumulate piles of numbers since those days. In the case of Japanese, we might prefer composing a poem for admiring its beautyof Mars or holding the tea ceremony under the sky. There is still tendency for Japanese to feel quantification to be less humanity, though it is a key step to do Physics.

こんにちは、トニーさん。「地球における日本」にコメントしてくれて有難う。
ええ、そうですね、古代ギリシアや古代エジプト文明などからの影響はとても重要ですね。
今回は物理学を進める上で必要となる2つの段階について触れようと思います。それは、

1) 数量化(データベース化)
2) 抽象化(法則化)

の2段階です。

16世紀、デンマークのチコ・ブラーエはなんと、16年間も火星の動きを詳しくノートに記録
しました。そのデータを解析して、ヨハネス・ケプラーは有名な「惑星運動に関する3つの
法則」を導きました。

チコの残した膨大な数字の羅列から法則を導きだした、このケプラーの洞察には驚くべきも
のがあり、その後、この3法則を説明するために、ニュートンの重力理論が生まれ近代物理
学の創始となっていきます。でも、私としては、そのきっかけとなったチコ・ブラーエの行
った自然現象の「数値化」の重要性に目を向けたいと思います。チコ・ブラーエの観測は恒
星を基準に測定した時は角度にして1分の誤差、通常は2分、惑星の位置に関しては4分とい
った高精度なものでした。コペルニクスが10分の精度での一致で満足していたのにくらべ、
各段の精度を誇っています。しかもその観測は裸眼だったのです。

ヨーロッパでは、そのころから「数値化」の重要性を認識していたことと思います。日本なら
さしずめ、火星を題材に俳句をひねるか、お茶会を開いて眺めるといったことでしょう。まだ
まだ日本では、「数値化」とか「数字の列」とかを人間味がないと敬遠する向きがあります。
でも、この数値化こそが、物理学にとって重要なステップなんです。

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Astronomy in Chocolate

Monday, March 30th, 2009

I went to the Chocolate Festival in Versoix, Switzerland on Saturday. As a tie-in with the International Year of Astronomy (by the way, here is the cosmicdiary blog), 13 chocolatiers made astronomy-related chocolate creations. You can see a few of them above (click twice for big versions) including my favorite, the bunny. Yes, that is a chocolate bunny astronaut planting a carrot flag.

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Whatever Works

Sunday, March 29th, 2009

hystogramEarly on in my student career, I learned that a favorite excuse of physicists is that we are beholden to take “whatever works” in the task of describing Nature. Sure, sure, we do give some degree of greater weight to “beautiful” theories (some of us moreso than others), but on the whole we are a culture of pragmatists. We tease our mathematician compatriots rather a lot for lack of proper respect for a correspondence of theory to reality. And in front of an experimental physicist audience, it really is best not to talk too loudly about things that cannot be proven one way or the other by observation.

But don’t let the simplicity of “whatever works” fool you. I can’t imagine that any good physicist would actually be happy to accept and/or use a method that just so happens to predict reality, without some kind of deeper understanding of why it works, how far it can be pushed, and where it can break down. In fact I would dare to say that in the majority of experimental physics analyses, only a small fraction of the effort goes into performing the measurement itself, and the rest is spent chasing down and quantifying all the uncertainties one has to acknowledge about various aspects of the method.

What I find quite amazing is that every generation of physicist manages to be trained in the scientific method almost entirely by example. In Math one is taught the rules of deduction, and there is little ambiguity in what constitutes a valid mathematical proof starting from the axioms and down every link in the chain onwards to the hypothesis. There is no such uniformity in Physics; in fact, there may not even be any requirement that a physics graduate have any knowledge of formal logic. Now, I don’t mean to say that the Quod Erat Demonstrandum structure of Math is or should be equally applicable to Science. While one can use “A→B” in Math to show that B is true (after having shown that A is true), the same statement in Science is only good to whatever uncertainty — and, more importantly, whatever other “hidden” variables went into controlling the behavior of A, B, and A→B. If scientists tried to achieve as much formal rigor in their reasoning as mathematicians do, I’m not sure we would be able to make appreciable progress. And this is where another “whatever works” often comes in — even if unable to fully list and/or address all the issues in the scientific chain, one can hope to do something reasonable, and then check the answer against some kind of control region (a.k.a. lab test) in order to argue that it should work in the region of interest.

If you think that the above paragraph is cryptic and rambling, imagine trying to convey the hows of this thinking process to a student fresh out of classes, where all theories and experimental results have been neatly laid out, and even with exactly the required pieces of information, no more, no less. The actual process of research is nothing so linear or finite. A good researcher has to keep an eye on almost everything, because it is anybody’s guess as to what is necessary, important, or prone to breaking. And just because “whatever works” happens to work, does not mean that one  has demonstrated that it is not a lucky accident. And unfortunately, it seems like the burden of scientific proof is one of the most difficult things to learn in this apprenticeship.

[ On the very incomprehensible drawing : The grey blocks are a histogram. The red things are for you to interprete. The background is supposed to be waves, but apparently those are way outside of my technical ability. ]

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Physicists on Bikes

Sunday, March 29th, 2009

I’m on my own this weekend since my partner, Tom, is off bike racing in Nevada. A surprisingly large portion of the Stanford Cycling team are physics graduate students. In fact, cycling seems to be the sport of physicists. To be fair to my non-American colleagues who go crazy during the World Cup: yes, I know you love football (soccer) more than cycling. But most people (except Americans) love football, while it seems like the only Americans who care about cycling are physicists.

Einstein on a bike!

The trend may be due to a certain picture of Einstien on a bike that many of us have seen (after all, it is hypothesized that the “sloppiness” of physicists is also in imitation of him). But why was he on a bike? Did he catch the cycling bug from another physicist, like I did? Cycling often serves as a bonding activity between physicists. During my graduate school orientation we were invited on a “geek ride”, but informed that bikes bought at department and discount stores would likely be insufficient. I regularly see spandex-clad groups leaving SLAC and have gone on numerous rides with other physicists.

Cycling provides an opportunity to push oneself physically, to think, and to be alone. Everything has physics behind it, but the forces are painfully obvious in cycling: wind resistance, friction, and angular momentum interacting with your balance. Unlike team sports, where you have to react to other people, cycling is about kinematic optimization. Can you speed up through this turn? Can you be more aerodynamic on this descent? While running is similar in some regards, I think cycling is an easier task. Anyone can start cycling, even if they are quite out of shape. They might not get too far or go very fast, but they can get somewhere.

I adore my bike and cycling, but don’t intend to ever race. I prefer biking alone and tend to keep a relaxed pace (and stop and take pictures). I sometimes challenge myself – I biked up Edgewood Road yesterday, which is more of a climb than what I normally do. It was a beautiful day out, a cool wind and not too hot, so I was one of many cyclists on the road. Yet the cyclists were outnumbered by butterflies; apparently there is a “painted lady” butterfly migration passing through the area right now. Now that the weather is consistently beautiful, I look forward to many more rides.

The view from the crest of Edgewood

The view from the crest of Edgewood

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