I can give it a try!

Condensed matter physics is rather broad (and probably, population-wise, the largest area of physics), encompassing the study of solids, liquids and generally squidgy stuff. As a theorist, I study simplified models of crystalline solids (materials where the atoms form a periodic structure) in an attempt to determine their properties (do they conduct? is it magnetic? etc).

The particular models that I'm most interested have two main properties: (i) the constituent particles (e.g., electrons) of the model are strong interacting; (ii) these particles are confined to move back-and-forth in a single direction. The first property makes these systems difficult to study as interactions often have surprising effects (properties of the interacting system can be completely different to the non-interacting system!) and we don't have many mathematical or computational tools to deal with such problems. The second property is rather special, but not completely crazy -- we do see real materials where particles are (approximately) confined to move in a single direct (through, e.g., quirks of the crystal structure). This restriction also saves us a bit, as there are a number of special technique which allow us to make headway with such problems, which don't apply when the particles can move in more than one direction.

The out-of-equilibrium problems I study basically aim to address the following question: if one dumps a load of energy in to a quantum system very suddenly, what happens? The natural conjecture is that if one leaves the system alone for a sufficiently long time, it should settle and become hot. In fact, it turns out that the story is quite a bit more complicated than that, and these kinds of questions are being studied quite a lot at the moment.

Tldr: I study collections of particles confined to move along a single direction which interact strongly. We want to understand how (and if) these systems get hot when you suddenly dump some energy in to them.