Physicists are using surprising ideas and mathematical tools originating in string theory to guide research into strange materials that are cropping up in condensed matter laboratories... “Let’s start here,” Sachdev says. “Condensed matter physicists study the behaviour of electrons in many materials – semiconductors, metals, and exotic materials like superconductors.” Normally, these physicists can model the behaviour of a material as if electrons were moving freely around inside it. Even if that’s not what’s actually happening, because of complex interactions, it makes the model easy to understand and the calculations easier to do. Electrons (and occasionally other particles) used in...