Research

Summary

The focus of our research is on quantum matter. Broadly speaking quantum condensed matter can be viewed as both quantum phenomena in conventional phases of matter and quantum order in strongly correlated materials. This includes, but is not limited to, quantum transport, Anderson transitions and many-body localization, non-equilibrium quantum dynamics, topological phases of matter, entanglement and quantum information. We have published papers on all these topics and continue to explore them further. These phenomena are realized in various systems; we have mainly studied topological insulators and superconductors, graphene, quantum spin-chains, 2D electron gasses and quantum dots, particularly in the presence of spin-orbit coupling.

Below we discuss some of these research topics in more detail. For further details we refer to our publication list.

Research topics

Many-body localization

The Anderson insulator is a quantum state of matter which does not conduct. This is due to disorder induced destructive interference of the electron wave function; a manifestly non-interacting, single-particle phenomena. What is the fate of this insulating state when the constituent particles interact among themselves? Will it become conducting or will it remain an ideal insulator? If the latter, what are the properties of the resulting insulating state?

Absence of localization

Disorder, when strong enough, generally localizes all electrons. An exception is electrons at the surfaces of topological insulators, which due to their nontrivial topological properties manage to avoid localization. This property can, in fact, be used as a definition of a topological insulators.

Topological insulator nanowires

Topological insulators are bulk insulators with a metallic surface which can be described, in the simplest case, by a single Dirac fermion. What are the properties of this metallic state when the surface is curved, such as in a cylindrical wire? How are these properties revealed in experiments, in particular in quantum transport? Are there phenomena unique to this system?