Topology and Chirality

TL;DR

This paper discusses the role of topology and chirality in condensed matter physics, highlighting how chiral electron states underpin phenomena like the chiral anomaly and their broader scientific implications.

Contribution

It reviews the significance of chiral states in topological materials and their connection to fundamental physical phenomena and other scientific fields.

Findings

Chiral electron states are fundamental in topological materials.

Weyl semimetals exhibit chiral bulk states enabling novel quantum phenomena.

Chirality links condensed matter physics to high energy and astrophysics phenomena.

Abstract

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.