Quickly put, I am a hard condensed matter physicist, specialisesd in first- principles study of materials at extreme pressure. But let's split it by parts...
Condensed matter is the area of physics that studies and predicts the behaviour and properties of macroscopic systems, such as a diamond or a copper wire (hard), to a glass of water, molten chocolate or a system of gases (soft). Astrophysics or nuclear physics are out of my scope, however.
A First-principles study is based on theoretical calculations performed with the minimum amount of approximations. In condensed matter, this means treating matter as a system of atomic nuclei and electrons, interacting as described by Quantum Mechanics.
Finally, extreme pressure is usually understood as larger than 1 GPa (gigapascal), which is almost 10.000 times the atmospheric pressure. For comparison, the pressure at the bottom of the Mariana trench, the deepest point in the sea, is only 0.1 GPa.
Because it's exciting! Pressure is able to change materials as much as temperature is. A short list of experimental feats would be:
Outside the lab, diamonds on earth have been formed at high pressure-high temperature, either on the mantle of Earth or on meteorite impact sites. The strong magnetic field of Jupiter is likely caused by the metallization of its primary element: hydrogen.
One of the nice perks of being a scientist is meeting people from all around the world, somewhere else. I've been a hobbyist photographer since 2009, and carried my camera with me to most conferences I've been to.
Here is a small sample of the pictures I've taken during conferences.