Hidden Dimensions

Phiphy's Physics Study Notes

Posts Tagged ‘the way of research’

Scientist: Four golden lessons (ZZ)

Posted by Phiphy on 07/17/2009

These are bloody correct lessons.

http://www.nature.com/nature/journal/v426/n6965/full/426389a.html

Steven Weinberg

When I received my undergraduate degree — about a hundred years ago — the physics literature seemed to me a vast, unexplored ocean, every part of which I had to chart before beginning any research of my own. How could I do anything without knowing everything that had already been done? Fortunately, in my first year of graduate school, I had the good luck to fall into the hands of senior physicists who insisted, over my anxious objections, that I must start doing research, and pick up what I needed to know as I went along. It was sink or swim. To my surprise, I found that this works. I managed to get a quick PhD — though when I got it I knew almost nothing about physics. But I did learn one big thing: that no one knows everything, and you don’t have to.

Another lesson to be learned, to continue using my oceanographic metaphor, is that while you are swimming and not sinking you should aim for rough water. When I was teaching at the Massachusetts Institute of Technology in the late 1960s, a student told me that he wanted to go into general relativity rather than the area I was working on, elementary particle physics, because the principles of the former were well known, while the latter seemed like a mess to him. It struck me that he had just given a perfectly good reason for doing the opposite. Particle physics was an area where creative work could still be done. It really was a mess in the 1960s, but since that time the work of many theoretical and experimental physicists has been able to sort it out, and put everything (well, almost everything) together in a beautiful theory known as the standard model. My advice is to go for the messes — that’s where the action is.

My third piece of advice is probably the hardest to take. It is to forgive yourself for wasting time. Students are only asked to solve problems that their professors (unless unusually cruel) know to be solvable. In addition, it doesn’t matter if the problems are scientifically important — they have to be solved to pass the course. But in the real world, it’s very hard to know which problems are important, and you never know whether at a given moment in history a problem is solvable. At the beginning of the twentieth century, several leading physicists, including Lorentz and Abraham, were trying to work out a theory of the electron. This was partly in order to understand why all attempts to detect effects of Earth’s motion through the ether had failed. We now know that they were working on the wrong problem. At that time, no one could have developed a successful theory of the electron, because quantum mechanics had not yet been discovered. It took the genius of Albert Einstein in 1905 to realize that the right problem on which to work was the effect of motion on measurements of space and time. This led him to the special theory of relativity. As you will never be sure which are the right problems to work on, most of the time that you spend in the laboratory or at your desk will be wasted. If you want to be creative, then you will have to get used to spending most of your time not being creative, to being becalmed on the ocean of scientific knowledge.

Finally, learn something about the history of science, or at a minimum the history of your own branch of science. The least important reason for this is that the history may actually be of some use to you in your own scientific work. For instance, now and then scientists are hampered by believing one of the over-simplified models of science that have been proposed by philosophers from Francis Bacon to Thomas Kuhn and Karl Popper. The best antidote to the philosophy of science is a knowledge of the history of science.

More importantly, the history of science can make your work seem more worthwhile to you. As a scientist, you’re probably not going to get rich. Your friends and relatives probably won’t understand what you’re doing. And if you work in a field like elementary particle physics, you won’t even have the satisfaction of doing something that is immediately useful. But you can get great satisfaction by recognizing that your work in science is a part of history.

Look back 100 years, to 1903. How important is it now who was Prime Minister of Great Britain in 1903, or President of the United States? What stands out as really important is that at McGill University, Ernest Rutherford and Frederick Soddy were working out the nature of radioactivity. This work (of course!) had practical applications, but much more important were its cultural implications. The understanding of radioactivity allowed physicists to explain how the Sun and Earth’s cores could still be hot after millions of years. In this way, it removed the last scientific objection to what many geologists and paleontologists thought was the great age of the Earth and the Sun. After this, Christians and Jews either had to give up belief in the literal truth of the Bible or resign themselves to intellectual irrelevance. This was just one step in a sequence of steps from Galileo through Newton and Darwin to the present that, time after time, has weakened the hold of religious dogmatism. Reading any newspaper nowadays is enough to show you that this work is not yet complete. But it is civilizing work, of which scientists are able to feel proud.

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杂记

Posted by Phiphy on 10/11/2008

一个人想法的多少难道是随着他的知识增长成U型变化趋势的吗?以前只知道皮毛的时候想法很多很大胆,跟民科一样,现在目不暇接地学了一堆东东却似乎什么都不敢想了,因为每一个想法似乎不是有人做过就是马上会被否定掉,经历了太多这样的情况就开始变得麻木了。真是有些担心,不知道学通之后真正有用的想法能不能多起来。就算做model builder, 我的目标也是总工程师。

今年的诺贝尔奖跟我正在关心的东西关系不小,如果有时间我会自己总结一个review,关于对称性自发破缺和费米子混合问题。

美国的高能实验快进入冬天了。美国政府的科研经费申请政策太弱智了,一个大型项目每年都要重新审批,砸了无数钱建到一半都能扔下,不想出钱又狂浪费钱,目光短浅的严重表现。现在好了,金融危机一闹彻底没戏了。

LHC最早在明年4月就能出第一批数据了,而额外维的引力子貌似是需要数据最少的。RS首当其冲啊,要死的话就是死得最早的。这样也好,省得我在上面白白浪费青春。

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A New Group Blog

Posted by Phiphy on 11/15/2007

We started a new group blog, discussing all the things we care about in physics.

SuperExtra

开博致辞:

学好物理需要什么?废寝忘食地看书还是埋头刻苦的计算?这当然是必要的,但是还不够。我们需要交流,活跃的交流,广泛的交流,不但要听,还要说,不 但要学,还要争。不过很遗憾,这样的交流氛围在国内外似乎都不够,特别是对于刚进入这个领域的我们而言。于是,在跟 Umbriel 达成强烈共鸣之后,我们决定用blog搭起桥梁,让远隔千里的我们能够有一个平台进行有效的学术讨论。

其实,利用网络的学术交流已经实践很久了。繁星客栈和格志便是论坛和blog的优秀典范。然而,论坛在国内的生存空间已经越来越小,繁星客栈和其他 很多学术论坛都已经因为屏蔽而不得不暂时关闭;而格志又因为作者太多领域太泛而降低了交流的效率。因此,我们这个blog不准备搞得很大,仅仅定位为理论 粒子物理和宇宙学及相关话题的讨论平台,参与的作者都是这个领域的研究生。为了提高交流的效率,我对作者们提一些建议:

1. 博文的内容主要为理论粒子物理和宇宙学,当然也欢迎数学、实验及其它相关话题。

2. 博文的形式可以很广泛,比如学习心得,科研介绍,疑难提问,文章评论,报告总结,实验谣言,历史八卦……总之要 keep going, 让我们的氛围活跃起来。

3. 既然这是讨论的平台,就不要当成个人空间。为了提高讨论效率,写出来的东西要尽量提供足够的知识背景,让大家看懂,因为虽然是同专业,但做的东西也不完全一样。当然也不用太科普,尽量学术化一些。

4. 博文语言中英文不限,不建议使用其他语言(包括火星文)。72pines支持\LaTeX输入(尽管没有wordpress自己的版本好看), 格式:[tex ]latex code[/tex] (不含空格)。
我希望这个blog能够结合个人日志和BBS的优点,对大家的学习研究有所帮助。

最后喉一声:让我们团结起来,为中国的物理事业奋斗终生!

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Some lessons

Posted by Phiphy on 10/19/2007

It’s not easy to start research. The first step is to get use to your advisor and learn many many lessons.

My advisor asks me to calculate a flavor model in the simplest case. It seems that what I am calculating always goes away from what he is thinking, and when I come back to look for his help after wasting a lot of time, he seems already know the answer to the next step. It’s so clear to him what will happen next, but I have to spend many time and energy on it before I see the simple point. I believe he would not even bother to talk with me on these problems if he was not training me. This is the distance between a sophisticated professor and a beginner, he have much more intuition, both mathematically and physically, that is, he can easily guess the result without any complicated calculation. I can’t, I lack the intuition and spent much time on meaningless calculations, I used too many parameters which I do not know how to simplify and have to use mathematica, and of course, no meaningful things came out. He told me not to use mathematica at this time, approximation is much more powerful than exact calculation for the first step of a model. He is right, I should think much before I calculate. I did find a much simpler way to calculate after all, although the setup was too simple to be right.

I find myself doing something I disgusted in my college – model building. I don’t want to become a professional model builder, although my advisor is, and he is really a successful one. In fact he gave me two directions to choose in the beginning, one is more formalistic, something on RS and string theory. I considered that one and gave up, although it’s somewhat closer to me early dream, because he is not a string theorist and string is not a good start point for me. I chose model building for a good chance to learn LHC related phenomenology and more about SM and beyond, but my long goal is not sticked on it. So I should keep in mind: I am not building model, but doing physics; I am not playing toys, but playing with the real world. I should try my best to find the more fundamental physical meaning for what I am doing. I think my advisor is trying to do this. He is not a pure model builder, at least, he is more like an engineer than a worker if we compare model building to house building. But now, I have to start as a worker – do what he tells me to do with the tools he provide to me. I have to make a change, as someone said, good graduate students can lead their advisor in the end.

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