Monday, May 14, 2012

The Problem Of Pursuing To Be A Theorist

First, a declaration. I'm NOT a theorist. I'm an experimentalist (and proud to be one, damn it!) :) So one can say that my take on this can easily be inaccurate and based on superficial observations. However, having looked at it for many, many years, and talking to many theorists for quite a while, I think I have a view that isn't too far off for someone who isn't one.

This thought came up because I keep coming across students just starting out (some even still in high school) wanting to be theoretical physicists. Neglecting the fact that many of them have a mistaken idea of what "theoretical physics" is, I think that most (if not all) of these kids do not realize just how difficult it is to not only graduate with a PhD in physics, but also having the chance to actually be employed as a theorist.

Let's start from the most obvious: there are more experimentalists than there are theorists working in physics. Regardless of the field of study (outside of string/etc, I mean), experimentalists tend to outnumber theorists, often by a lot (see, for example, condensed matter physics and accelerator physics). So already the "phase space" for employment does not look very appealing to theorists.

Experiments and experimentalists tend to bring in more funding to a particular institutions. Now granted that in many of these funding, both theorists and experimentalists are involved. But even in such situation, the funding proposal tends to have more experimentalists than theorists. This is also one reason why there are more employment for experimentalists than theorists.

A project may get by without a theorist, even if it requires theoretical work. More often than not, an experimentalist can pick up the task that a theorist does, but it is more daunting for a theorist to do an experimentalist job. I'm not saying that this is true all the time, but in my experience, I've seen experimentalists do theory (especially in high energy physics), or use tools such as packaged software to perform theoretical simulations (especially in accelerator physics) without officially needing a theorist. Now, they may consult a theorist on site, but such tasks are often done by experimentalists without needing to employ another theorist to do such jobs. I haven't seen the reverse yet in my experience, i.e. group of theorists taking on jobs done by experimentalists, without needing to hire or have the presence of experimentalists. In fact, last time a theorist got close to my vacuum components, he ruined it by touching a clean part with his bare hands!!

Finally, the competition for the few positions in theoretical physics, be it in Academia or other institutions, is fierce! I do not envy the theorists at in this aspect. Because of the small number of positions available, even the good ones will have a tough time finding a job in their respected fields. In fact, if you did not come from a top-tier school, and your mentor isn't a "brand-name, world famous theorist", there's a very good chance that you will not get accepted to such a position in a good institution in your field. I think that the "pedigree" factor is a lot more prominent for theorists than for experimentalists, mainly because of such limited job opportunities. There are just too many outstanding candidates. What this means is that newly-minted PhDs from less well-known schools or supervisors seldom have a chance for employment as a theorist in their fields, leading to many to go into other fields or even outside of physics completely.

I'm sure there are many exception to what I've just described. But I believe that, on average, this is what is going on based on my years of observation. So, are you a theorist? Did I get it right, or was I just blowing smoke?

Zz.

15 comments:

The Universe said...

I'm not a theorist either, but I know an awful lots of people with a physics PhD who aren't doing physics for a living. You aren't blowing smoke, Zapper.

John Duffield

JRA said...

As a nearly-minted theory student I can say that you're pretty much on the mark. Theory students are cheap, but postdoc jobs are rare (think a few offers per 100 applications), and faculty positions are rarer.

I would say that many of the experimentalists that you would trust to do a theory calculation (in particle physics at any rate) are former theorists - It's possible to successfully do the switch from theory to experiment after your PhD, but I've never heard of the opposite.

ZapperZ said...

JRA: I tend to agree with you that, in particle physics, former theorists can possibly be "experimentalists" (in a very loose sense). This is because from what I can gather, high energy experimentalists tend to do a lot of data analysis (I would say, overwhelmingly just that), rather than having to deal with the nuts and bolts of an experiment, like the rest of us in physics. So I suppose a theorists can find a home in such a place after all.

Zz.

JERVIS said...

I think that in the first place by looking at science as a means of getting employment and constantly worrying about your job & funding prospects rather than your science is to a sign of the commercialism in science today. Its not that these matters are not important, but if all that you wanted was a job, you could have gotten it with less pain and better money in other fields. Great Science was done in the past by people who were not professionally employed as scientists, for instance say Kepler. Today in the name of funding good ideas are blocked by more powerful figures in academia.
I think that the field of Science should become more accountable and transparent to the public at large. There are many obvious ways of doing it but certain vested interests have blocked these measures for decades.

ZapperZ said...

You made unsubstantiated and, frankly, rather silly argument here.

First of all, would you rather we go back to the good, ancient days of doing science? I don't! Science back then were done by those who can afford an education, meaning those in the upper class society. Secondly, there were very little peer-review done. You want to go back to such a system?

And where exactly are good ideas blocked by "powerful figures in academia"? You talk as if you are completely ignorant of the funding system in the US. Are you? Have you gone through the funding system and seek research grant in one form of another?

Just because you said so doesn't mean its true. This is still a physics forum. If you can't back up what you just said, don't expect any more of your comments to be released on here.

Zz.

Massimo said...

It is your opinion and it is based on your experience, so I respect it. However, I think it may reflect the situation in your own field more than in physics as a whole. In particular, wish to point out the following:

Let's start from the most obvious: there are more experimentalists than there are theorists working in physics. Regardless of the field of study (outside of string/etc, I mean), experimentalists tend to outnumber theorists, often by a lot (see, for example, condensed matter physics and accelerator physics).

In accelerator physics yes, for sure, but that is an unfair comparison given the size of the experiments, which sets HEP apart from essentially all other fields of science.
In condensed matter physics I estimated a few years ago the ratio E/T to be 1.5:1. You may take issue with this figure, but assuming that it is more or less on the right ballpark, is that "a lot" ? And with the cost of experimental research and decreased funding I believe that that will go down in the years to come.

Experiments and experimentalists tend to bring in more funding to a particular institutions.

True, but a large portion of the funding acquired for experiment must be utilized for the purchase and/or maintenance of equipment, on which experimenters are crucially dependent. Theorists can be more flexible in that regard (take away the computer from me and you will set me back considerably, but I can still do something). So, when it comes to supporting graduate students or postdocs, it is not clear to me at all that experimentalists do the bulk. Of course, you may have data to back this contention up.

A project may get by without a theorist, even if it requires theoretical work. More often than not, an experimentalist can pick up the task that a theorist does, but it is more daunting for a theorist to do an experimentalist job.

Yeah, that does sound like the opinion of an experimentalist ;-)

Finally, the competition for the few positions in theoretical physics, be it in Academia or other institutions, is fierce! I do not envy the theorists at in this aspect.

Huh ? Are you saying that there are more applicants per position in theoretical than in experimental physics ? Again, do you have data to back this up ?
My rough estimate, for example based on sites like the condensed matter rumour mill, is that the ratio of available positions is fairly close to the E/T ratio.

ZapperZ said...

1. First of all, accelerator physics is NOT the same as high energy physics. Accelerator physics is a separate subject area. Many accelerator physicists don't even take a class in particle physics in school. So confusing those two is VERY bad.

2. I came from a condensed matter physics background. My observation came from 3 US National Labs and 2 US universities. The ratio of experimentalists to theorists in those institutions are roughly 5:1. I consider that to be "a lot" of experimentalists when compared to theorists. And I'm counting postdocs as well.

3. The competition is more fierce in theoretical physics because of the scarcity of the job. I've mentioned this earlier for high energy physics.

http://physicsandphysicists.blogspot.com/2010/02/job-outlook-for-theoretical-high-energy.html

Zz.

Massimo said...

First of all, accelerator physics is NOT the same as high energy physics

Hey, look, I made a "very bad" mistake and I even signed my name, so, that will serve me well, won't it ?
Anyway, it seems like you are nit-picking and not really addressing the main point. I agree that I did not phrase my comment properly. I meant to say that what I wrote about accelerator physics could extend to the whole of HEP, a wider field to which accelerator physics is strongly connected, if it is not a branch of it. Neither could be in fairness regarded as representative of the whole discipline (physics). I still stand by comment, replace "HEP" by "accelerator physics" if you wish but it seems besides the point.

My observation came from 3 US National Labs and 2 US universities. The ratio of experimentalists to theorists in those institutions are roughly 5:1. I consider that to be "a lot"

OK, I am a bit confused here: my 1.5:1 ratio is based on data for the top 25 US universities (I gave you the pointer). Are you saying that my data are wrong ? If so, can you please point me to the correct ones, or offer alternate data ? Or, is your point that your personal observation of "3 national laboratories and 2 universities" should supersede or invalidate my data ? I think that any claim of a 5:1 ratio at the university level is not even worth debating.

The competition is more fierce in theoretical physics because of the scarcity of the job. I've mentioned this earlier for high energy physics

Yes, you may have "mentioned it" but I was asking for data, which you are not providing here, nor on the original post, it seems to me. "Mentioning" something does not make it true.

ZapperZ said...

Well, I think you made another boo-boo here. :)

Accelerator physics is not even "strongly connected" to HEP. The overwhelming majority of accelerators in the world have nothing to do with HEP (look at synchrotron centers, medical accelerators, etc.). In fact, BES division of the DOE's Office of Science is a major funding agency for accelerator physics research.

Secondly, the ratio of experimentalists to theorists in Accelerator Physics is even higher than in HEP. This is where the work of theorists can often be done by experimentalists. This is because theorists in this field had done such a good job in producing excellent codes for many types of simulations.

Thirdly, yes, since you claim to have covered more "data", then certainly you would have a better evidence than I do. It is still difficult for me to be convinced of that, though. I'm looking at the condensed matter program at U. of Chicago and UIUC, and I don't see that kind of a ratio that you are talking about (again, number of faculty and postdocs). And I don't think what you did is any different than the analysis that was done by Poppitz that I mentioned in that blog article.

Zz.

Massimo said...

OK I think we can agree on the following:

1) I know little of nothing of accelerator physics, to the point of even believing that it has something to do with HEP (the nerve of me), when in fact, it has absolutely nothing to do with it.

2) Aside from the above all-important aspect, however, that accelerator physics is not representative of the whole field of physics is something that I think you cannot dispute. Thus, one cannot assume that the ratio E/T in the whole field of physics (to which your original post applied) is greater than 5 because it may be so in accelerator physics.

3) Your statement on the ratio E/T is not based on anything that could in fairness be called data. Your personal experience is perfectly respectable, of course, but so is mine and that of anyone else. This is why I still think it is better to try and collect data.

4) I have not "claimed" to have data, I have data, they are published, and I posted a link.
You can go and dissect them if you wish. I have already written it twice and I repeat it: if they are incorrect, if you question my methodology, if you think you have better data, please educate me and your readers. I shall publicly thank you for that.

5) Your statement on there being more academic jobs for experimentalists than theorists across the whole field of physics is also not backed by data.

ZapperZ said...

1. I'm not being nitpicking, but I need to correct a wrong conclusion here. I NEVER said that accelerator physics has "absolutely nothing" to do with HEP. What I did say is that an overwhelming majority of accelerator physics (as in the APPLICATIONS) has nothing to do with HEP. I gave you examples. I can also point to you the excellent article "Accelerators and Dinosaurs" by Micheal Turner:

http://physicsandphysicists.blogspot.com/2008/06/accelerators-and-dinosaurs.html

2. Correct. I didn't say that the example in Accelerator Physics is representative. I used accelerator physics as an example where the work of a theorists can often be done by experimentalists. The group that I belong to has ZERO theorist, even though we need theoretical simulation and understanding to design accelerator structures, understand beam physics properties, etc.

3. I also never claimed to have a verified data beyond what I've observed over the years. I thought I made this abundantly clear in the beginning of the blog article. This is never in dispute. However, I do not claim that this is ONLY from academic jobs. If you look at the condensed matter "divisions" at, say Brookhaven or Argonne, you'll find that 5:1 ratio in terms of experimentalists:theorists. In fact, I would GUESS that this ratio is even more severe, because it doesn't count the condensed matter experimentalists that are not in their division but in the "synchrotron" division (APS division at Argonne, NSLS at Brookhaven). I intend to look closer at SLAC and Berkeley.

Zz.

Matthew said...

I know this post is fairly old, but it most relevant to my comment/question. I am an aspiring PhD student trying to figure out my path of study. I'm primarily interested in experimental physics, but I have some interest in computational physics and I am wondering about the prospects of this post-PhD. Perhaps you could provide your opinion (or reference a previous blog I haven't seen) on the field and the trends you've seen? Thanks!

ZapperZ said...

I'm not sure that you need to make a choice between the two. I've seen plenty of cases where experimentalists were also doing computational work. Again, to bring out the example from Accelerator Physics, computational work is a HUGE part of the field, and practically every experimentalist (and theorist, for that matter) in that field also do extensive computational physics work. So in such a case, you don't have to make a choice between one or the other.

Zz.

monu said...

I am an aspiring theoretical physicist. I am primarily interested in high energy physics,gravitational physics,cosmology etc. Okay, i am an undergraduate student so i do not have in depth idea of these fields but i have read popular books on the subject and find the open questions in these fields pretty much challenging and exciting. But the following link http://wuphys.wustl.edu/~katz/scientist.html
discourages me from doing so. The same can be said about you too. Could you please enlighten me on the subject. I am hell bent on devoting my entire life to science.

Alessandro Monteros said...

I know this is old but I figured I would let you know that I enjoyed reading your perspective on this matter. I am doing my Master's research in theoretical condensed matter but I am debating doing experimental condensed matter for my PhD. This article gave me an interesting perspective to help form my decision.