A fresh twist in chiral topology
The concept of chirality is well-established in science: when an object cannot be superimposed on its mirror image, both the object and its mirror image are called chiral. In the drug industry, for instance, more than 50% of the pharmaceutically active molecules used nowadays are chiral molecules. While one of the 'enantiomers' is life-saving, its counterpart with opposite handedness may be poisonous. Another concept which has found widespread interest in contemporary materials science is topology, as many so-called topological materials feature exotic properties. For example, topological materials can have protected edge states where electrons flow freely without resistance, as if a superconducting path of electrons were created at the edge of a material. Such unconventional properties are a manifestation of the quantum nature of matter. The topological materials can be classified by a special quantum number, called the topological charge or the Chern number.