Theoretical Quantum Matter – LPS

Activité scientifique

The Theoretical Quantum Matter group at LPS investigates two main areas in which quantum phenomena arise in condensed-matter systems. The first one is related to the miniaturisation of metallic and semiconducting circuits at length scales that require a full quantum treatment, such as in mesoscopic electron or spin transport. Not only need the material constituents be described quantum-mechanically but also the coupling to the environment, e.g. in electronic cavity-QED systems or in the study quantum noise. A second area is that of topological and relativistic Dirac materials in two and three spatial dimensions and its potential applications. In this case, even prior to miniaturisation of the circuits, the electronic material properties require a full quantum-mechanical treatment in terms of the Dirac equation and variants of it. This situation arises, e.g., in graphene, 2D transition-metal dichalchogenides and associated heterostructures, in 2D and 3D topological insulators and superconductors and also in 3D Weyl semimetals. The group is interested in the understanding of phenomena that arise due to these exotic bulk properties as well as in the evolution of these phenomena in meso- and nanoscopic devices where boundary effects play an important role.

Figure: A magnetic impurity in a superconductor gives birth to in-gap bound states with long spatial extent which might be used for topological quantum computing.  The figure represents the calculated spatial map of the local density of states of a magnetic impurity embedded in the two-dimensional  superconductor NbSe2 (Mateo ULDEMOLINS, 2022).