PhD defence: Electric and heat transport in two-channel Kondo systems

In this thesis we theoretically study a certain class of materials, namely solids that have a crystal structure on the atomic scale, such as most metals, diamond and table salt. For such materials, quantum mechanics tells us that the electrons cannot simply do whatever they want, but can instead only be in very specific states. If there are many easily accessible states, the electrons can freely move around between the atoms that make up the material, such that the material supports electrical currents and is therefore a conductor; if this is not the case, the material is an insulator. However, materials or devices in which the electrons are strongly interacting often have much more complicated properties.

The goal of this thesis is to advance our understanding of such exotic materials by studying the electric and thermal transport properties of a specific strongly interacting nanoelectronic quantum dot device. In practice, whether or not a material can have unconventional properties is often determined by measuring the electrical conductance and the heat conductance and calculating their ratio.

One of the most important results of this thesis is that this common method does actually not always work: we provide an explicit example of a device with proven exotic behaviour, which does nevertheless not show any signs of such behaviour in the ratio of the electrical conductance and the heat conductance. This is an important step in the quest to properly understand strongly interacting materials, which can potentially have useful applications in future technology.