Sheldon: I agreed to speak to you this evening because I was told that you're the best and the brightest of this university's doctoral candidates. Hmm. Of course, that's like saying you are the most important electron in a hydrogen atom. 'Cause you see, there's only one electron in a hydrogen atom. Best and brightest my sweet patootee. All right, let's begin. Show of hands, who here is familiar with the concept of topological insulators? Don't kid yourselves.