Another question that stumps me.
'What is your work?'
I've given so many variants of the same answer, and I don't know if any of them satisfied. Let me try again. Always good to write it out. How do I do this without jargon?
I study and make predictions about exotic materials. Some of these materials exist today and are subjects of experimentation; some exist only in my fantasies, and may never be realized in nature. I tend to study materials which allow a nice mathematical description. Because it continually astonishes me that pretty mathematics has anything to do with reality, that there is some order in this big mess. Also because pretty mathematics is challenging to grasp and apply, and I love the challenge.
Lately I've become interested in a strange variant of the humble insulator, which traditionally does not conduct electricity at all. However these new insulators have been found to conduct in a thin layer that is their boundary, the layer that is in contact with air. We characterize these insulators by their symmetries, which is to say, what are the different ways we can view this insulator, while not being able to distinguish its properties between one viewpoint and the next. For example, let's fix a point on the insulator, and imagine we are a small observer looking out from this point. If we rotate our view by 90 degrees, can we distinguish what we now see from what we saw previously? If not, we say the insulator has rotational symmetry. There are other interesting symmetries. Suppose we were watching a collection of particles zooming about in a box, doing their business of being particles and whatnot. Now FREEZE, reverse the velocity of each particle, PLAY. If the particles exactly retrace their original trajectories, as if the movie is replaying itself backward, then we say there is time-reversal symmetry.
Suppose we knew all the symmetries that characterize an insulator, then the next step is to formulate a mathematical quantity, that arises because of these symmetries, and can only take on integer values: 1,-1,0, etc. With these integer quantities, we classify these materials, much like how we classify anything in science. Often but not always, saying that a material is characterized by 1 instead of -1 means that it will exhibit different properties when probed during an experiment. For example, an integer number called the Chern number tells us: if we apply an electric field in one direction (say 'x'), then a current flows in 'y'. Suppose we divided (current/electric field), this quantity does not take any arbitrary value - it is the product of the Chern number and some fundamental constants (like the charge of an electron).
In this field, the predictions by theorists outpace the search for these materials and their experimental verification. There is an industry in finding the material, that is, identifying exactly what elements, when put together in what ratios, produce something exciting. I try to involve myself in this. Once identified, there is an industry in growing these materials, which is often done in a chemistry laboratory next door. I don't do this at all. Once grown, there is an industry in making experimental predictions that can reasonably be tested in a physics laboratory, something I try to do. Finally, there is the actual experiment, which I admire from afar, though I may get the chance to interpret their experimental data.
Ok, so how do I say this coherently in one minute, during a random conversation?
