A journey through transport phenomena and holographic interactions in Weyl semimetals

Abstract

Following the discovery of topological insulators (TI) in 2005, a quest has begun in condensed-matter physics, for the discovery of more exotic topological phases of matter. One such example are Weyl semimetals (WSM), materials whose valence and conduction bands touch at a singular point in momentum space. Although these states of matter come with a number of interesting features, in this thesis we focus on their transport properties. More specifically, we concentrate on the ability of WSMs to support an electric current in the direction of an applied magnetic field, a phenomenon that came to be known as the chiral magnetic effect (CME). On the way, we come across a crucial interpretation issue, whose resolution will require bringing together physicists working on tremendously different energy scales. After establishing a consistent and physically acceptable theoretical framework, we briefly turn our attention to the current experimental status of CME. The thesis concludes with the construction of a simple holographic dual theory to WSM, through which we hope we could gain some insights into the interacting regime of WSM. Interactions are potentially of particular importance in experimental attempts to identify WSM and CME. Therefore, a model that successfully takes these effects into account is urgently on demand.