HATS stands for Holography and Topological Semimetals, and is the name of my Marie Skłodowska-Curie Actions postdoctoral fellowship. All of my research since September 2023 has been funded by the European Union through this fellowship.
On this page I describe the background and motivation for this research project. You can find more technical information on CORDIS, the EU’s website for research results.
Quantum Field Theory
Quantum Field Theory (QFT) is a mathematical framework used in particle physics and condensed matter physics (the physics of materials). Different QFTs are used to describe different physical objects and systems. For example, the standard model is the QFT used in particle physics to describe how elementary particles interact with each other. In condensed matter physics, different materials are described by different QFTs.
The equations that arise in QFTs are usually impossible to solve exactly, so physicists use methods such as perturbation theory to obtain approximate solutions. However, these methods do not work for QFTs describing particles that interact very strongly with each other.
Holography
Holography, also known as the AdS/CFT correspondence, relates different physical systems. Two systems related by holography are said to by “dual” to one another. Holography allows predictions for one system to be made by performing calculations in its dual. This is very useful when the equations describing the dual system are much simpler.
Weyl semimetals
Semimetals are materials with properties somewhere in between those of metals and semiconductors. They conduct electricity, but only weakly. Weyl semimetals are a new class of semimetals that were experimentally discovered in 2015. One reason that they are of interest is because their unusual conduction properties may allow them to be used in novel electronic devices.
Some Weyl semimetals are described by strongly interacting QFTs, meaning they cannot be described by perturbation theory. The goal of HATS is to use holography to build and study models of strongly interacting Weyl semimetals.