Station Q Zurich
This is a subgroup focusing on topological quantum computing. Several research directions are pursued with the ultimate goal of creating a topological quantum computer. To support experimental efforts we perform simulations on the following topics
One of the research directions is to find the material with just the right properties for realising a topological quantum bit. We faciliate our search with a combination of first-principles and first-principles derived tight-binding models.
First-principles derived tight-binding models allow us to very efficiently simulate material-interfaces in the nano-scale region. Understanding of these interfaces is vital for correctly modelling quantum-devices.
Our goal is to optimise the design of the experimental devices in order to create the conditions best suited for observation of topological effects. This requires tuning of the electronic density and its position in a semiconductor heterostructure as well as tuning the properties of the semiconductor- superconductor interface. We perform numerical self-consistent Schroedinger-Poisson and analytical calculations for models that attempt to include most of the sample design details and should thus lead to realistic predictions for particular devices.
One particular area of interest is the relatively new but rapidly growing research field of Majorana fermions in topological transistors. In order to build machines which can exploit the remarkable properties of Majorana particles in condensed matter systems, we need to acquire a meticulous understanding of every component involved. A key element of topological transistors are superconducting materials. By developing methods for precise calculations of the fields within and outside the superconductor, we strive to facilitate the construction of geometries which induce magnetic fields that cause as little disruption as possible to these highly sensitive systems. Our group aims to numerically calculate the fields, Cooper pair density and quantum vortex distribution within arbitrary three-dimensional superconductors using the Ginzburg-Landau theory and visualise the regions of superconductivity loss and field penetration.