  Topology, a well-established concept in mathematics, has nowadays become
essential to describe condensed matter. At its core are chiral electron states
on the bulk, surfaces and edges of the condensed matter systems, in which spin
and momentum of the electrons are locked parallel or anti-parallel to each
other. Magnetic and non-magnetic Weyl semimetals, for example, exhibit chiral
bulk states that have enabled the realization of predictions from high energy
and astrophysics involving the chiral quantum number, such as the chiral
anomaly, the mixed axial-gravitational anomaly and axions. The potential for
connecting chirality as a quantum number to other chiral phenomena across
different areas of science, including the asymmetry of matter and antimatter
and the homochirality of life, brings topological materials to the fore.
