Wednesday, May 30, 2012

What Does It Mean To Be An Experimentalist?

OK, so last time, I tackled the issue of pursuing to be a theorist. Looks like up to this point, I didn't get hate mail for getting it wrong or having the wrong assessment of that profession. Since I survived that in one piece, I will now tackle something I know quite a bit more - being an experimentalist. However, since I seldom learn my lesson, I will tackle head on on areas of physics in which the term "experimentalist" can be rather vague.

For most of us, when we talk about an experimentalist, the image of someone in a lab coat, bending over a table full of chemicals, etc. would come to mind. While this may be true in fields such as chemistry or biology, nothing can be further from the truth in physics. In all the years that I've been an experimentalist, I've never worn a lab coat (I don't even own one, ever!). The interesting thing about physics is that it is such a wide and varied field, and consequently, the experiments that we do can look very different from one field to another, and even within the same field!

My intention to bring this up is based on a comment made by JRA in that theorist blog, and also based on my observation and conversation with other experimentalist. What does it mean to be an experimentalist in physics? If you are like me who came out of an experimental condensed matter program, chances are you had to build/assemble/maintain a vacuum system, had to perform your own diagnostics, do your own measurement, mount your own sample, do your own repair, etc.. etc. You are also in a relatively small group, and you do most of the experiments/work yourself. If your work gets published, more than 80% of the work that being reported probably involved you more you directly. In many cases, you also get to design the equipment, procure the parts, and then assemble it, often with help from engineers, etc. if you're lucky. The point here is that, in such a situation, you really are doing hands-on stuff, get your fingers dirty, crawl on your hands and knees, and doing physical labor work.

Now, on the other hand, if you are a high energy physics experimentalist, chances are, you spend most of your time in front of a computer, watching data come in, and spending most of your time doing analysis, or simulations, etc. There's a good chance that you didn't build the instrument that you are using, and that you hardly deal with the hardware involved in your experiments. I don't think that you're expected to build anything. The exception in such a situation is if you're building or designing a detector. In high energy physics, often the physics of the detector is part of the field itself. High energy physics often have to innovate and design its own detectors, since they can't simply open a catalog and buy one. But even then, the actual building and assembly are often done by technicians and engineers. In other words, if you are a high energy experimentalist, chances are you don't actually perform and control an experiment. This is probably why, as JRA has said, theorists can sneak in and be involved in experiments, thus, becoming experimentalists.

I may have described the two extreme cases here, and certainly there is a whole spectrum in between those two. Other fields of physics have varying degree of work. In accelerator physics, a lot of work done by physicists look more like engineering than physics, which is why accelerator physics is often populated by both physicists and electrical engineers. Still, we come back to our original question. What does it mean to be an experimentalist? I know that my example of a condensed matter experimentalist is what I can unequivocally categorize as being an experimentalist. But would my description of a high energy experimentalist be something what we consider to be an experimentalist? I talked to many high energy physics grad students and postdocs, and all they do is write codes, do Monte Carlo simulations and/or analysis, and data processing. They sound more like programmers to me, and I don't consider programmers as experimentalists.

So do you consider them to be experimentalists? Are you a high energy physics experimentalist with a different experience than what I just described? Do you consider yourself as an experimentalist?



Unknown said...

I once walked into the lab and saw one of my colleagues doing something with laser dyes, I don't use dye lasers so it might as well have been alchemy to me.

Anyway this fellow was wearing a lab coat. When I saw him, I immediately exclaimed (almost without irony) "Rich! You look like scientist!".

ZapperZ said...

Did he feel insulted? :)


Ukko El'Hob said...

...good science needs both "experimentalists" and "theoretician". Why this dichotomy? Who benefits from it?

ZapperZ said...

We need it because people like you can't get the topic and meander into irrelevant point.


Logan Wright said...

I have been mulling this over since your last post, so there are a few points to be made. These posts are very timely: I am starting a PhD and have been struggling to make sense of what seems to be two potentially very different day-to-day experiences and even two very different paths. First: whatever an experimentalist is, the typical undergraduate physics education contains next-to-nothing like it. I went through a pretty realistic engineering physics program and while I experienced a couple projects that were close, a few labs with some pretty wide-open guidelines and a thesis, none of these really give you a feeling of what being an experimentalist is. Speaking second hand of my peers in pure physics at mine and other institutions; they have far less in most cases (some students/schools have fairly involved theses, which accomplish this well enough). I was lucky enough to spend a lot of time in experimental labs in the summers, however, and theorists/computational theorists might have similar feelings about the lack of correspondence to their own work.

Physics education is inundated with theorists. Most of the undergraduate professors are theorists and, for undergraduate topics, most of the textbooks are written by theorists. Suppositions that this might lead to derogatory treatment of experimentalists are probably paranoid but it certainly means that undergraduates generally gain a great appreciation for theorists (maybe the best known experimentalist, who was brilliant, is known for a failed experiment he wrongly believed to be providing an incorrect result). Even if some actually develop a resentment towards theorists, they will learn physics in a way which is somewhat divorced from reality. I think one rapidly learns while doing an experiment to be very sceptical if it ever appears that the theory and experiment are in agreement! I really am in love with the theoretical pictures but in experimentation I do tend to first be surprised at how utterly different the reality is from my mental portrayal in very visceral way. True, it is also beautiful to see the theoretical depiction mirrored in reality but I feel as if I've learned physics in a way where only a sort of cartoon (admittedly a very precise cartoon!) would not cause some dissonance. This is one reason I like the exploratory lab, where one learns physics in a much more visceral way. And too, one carries out a lab to prove that a theorist is correct (save for the sorry incompetence of the experimenters); if the theory is wrong it is almost invariably a game of assessing one's experimental errors. But at least as often, an actual experimentalist must assume the experiment is right and try to find the error in the theory. It is maybe a subtle point, but as I do experimental work I always feel that I am on the edge of fluency. That is, I am speaking in experiment but thinking in theory.