******* Theory ******* .. toctree:: :hidden: many-electrons dft re On these pages we are going to briefly introduce the theory behind the physics that the iDEA code is trying to unravel. We aim to cover all the essentials, but if you're looking for more complete treatments, we strongly recommend the following two books: 1. `Interacting Electrons: Theory and Computational Approaches `_ by Martin, Reining and Ceperley 2. `Electronic Structure: Basic Theory and Practical Methods `_ again by Martin The second book goes into a little more detail on the basics than the first, so might be a better starting point for beginners.