Day: December 14, 2016

PhD Defense Grumpiness


Two of my students graduated in the span of a week. Essentially everyone but me who was on their committees was an experimentalist, with the exception of one pen-and-paper theorist.

Let me tell you this: developing computer simulations of the physical world which have real predictive power is very complicated. It requires understanding experiments, being able to understand and/or develop an appropriately detailed mathematical model, and then being able to develop and computationally implement an algorithm to numerically solve said mathematical model. It requires the skills of an old-school pen-and-paper theorist along with the skills in the computational sciences. The work is challenging and requires careful attention to detail; if you don’t know what you are doing, it will be garbage in, garbage out.

When I read experimental dissertations and attend defenses, I hear about all the details of growth, fabrication, and various characterization and measurement techniques. I consider it important to understand what those are.

Yet, whenever I present my group’s work, I have to always wave away the details of what I do because people don’t care. I have to care about various chemicals used for etching this or that, but it’s totally okay that my colleagues don’t care about the mathematical model that actually resulted in some graphs. I guess “math is hard and boring” applies to the mindsets of middle-schoolers and professors alike.

It pisses me off that my experimental colleagues cannot be bothered to try and understand the details of what my student did — at least at the student’s defense. The defense should be a time when students get to talk, at least a little bit, about the cool things they did, because that’s why they are getting a PhD.

Basically, no matter how long I collaborate with an experimentalist, they only ever care if the simulation is completely done with all the bells and whistles so that it matches perfectly with this or that, and they don’t care at all that it takes time to get to such high levels of quantitative agreement, that there are natural stages in the development of a detailed simulation, and that I cannot keep a student around for 15 years. What they want is only the information about what is yet not in the simulation and the reasons why it’s not yet perfect, rather than talking about how exactly we already got it to capture 85-90% of the physics.

Why the hell do I do this job, again? Seriously?

The other day I met a theorist who does old-school pen-and-paper theory. There was not a graph to save a life in his presentation. The dude publishes in Prestigious Society Letters far more often than I do (pedigree matters; also, PSL clings to this old-school theory and it is very hard to get much of the more modern or more applied topics past their reviewer base. I have spoken with some editors and they are all surprised why their impact factor is suffering — it’s suffering because they have not adapted to the reality of where the action is in the area that caters to the largest physics field today; journals published by a couple of other publishers, including a large society, have not had that problem and are now sporting impact factors twice or three times that of PSL. But I digress). Anyway, nobody among my experimental colleagues would have any patience whatsoever with me if I were to throw equations around with quantities in arbitrary units, only in the limits of what I can compute analytically (hint: very little), and only rarely show any actual data.

DH says that I shouldn’t care what anyone else thinks and that I do what I do because I love it. I am not so sure any more. I am kind of sick of it all.

Sick of always being second fiddle to experimentalists — more of an unpaid intern or a serf really; I sure as hell have to find my own money to do the work. Sick of working really hard and always only being asked why it isn’t all absolutely perfect yet, with anything that anyone could  possibly imagine computable in a heartbeat. My former postdoc has this great saying, that he feels people think we theorists receive a giant magic box with a million buttons (presumably when we are admitted to the secret society of theorists), so that whatever anyone imagines being calculated about any physical system just requires pressing a button on the magic box, and then people get cross when they want some specific data from us and we sit on our lazy a$$es and take our sweet time pressing the button.

And then some student from the audience asks why we do this complicated theory, can’t people just buy software to do this? I almost blew my top off. No, there is nothing commercial that is even remotely like what we are developing.

But this conveys another aspect of why everyone has such a low opinion of theory and simulation — they think what I do is the same as what they do when their boss buys them some canned software and they play around with it. That’s what 99.99% people have in mind when they say “I am so cool, I can do both experiment and theory.” No, you cannot. Developing new simulation techniques and running canned software are not the same. It’s night and day.

This is all such bull$hit. Why do I even bother?

Such bull$hit.

I cannot wait to go to a conference in my subfield in June.