PhD Defense Toivo Hensgens: 'Emulating Fermi-Hubbard physics with quantum dots'



12:30 hrs


Aula, TU Delft


Emulating Fermi-Hubbard physics with Quantum Dots. Promotor: L.M.K. Vandersypen (TNW).

Interacting electrons on material lattices can build up strong quantum correlations, which in turn can lead to the emergence of a wide range of novel and potentially useful magnetic and electronic material properties. Our understanding of this physics, however, is severely limited by the exponential growth in complexity with system size, which leads all classical methods to fall fundamentally short.

In this thesis, I show how artificial lattices of conduction band electrons in semiconductors, so-called quantum dot arrays, can be used to directly emulate and therefore elucidate such Fermi-Hubbard physics. To this end, I focus on two approaches. A top-down approach allows to scale easily, but lacks to ability to control or measure individual sites. A bottom-up approach utilizes the small devices employed by the community for qubit experiments, in which the control of individual sites is both a blessing and a curse. I address the issue of control to the point where mapping to relevant models is possible and efficiently calibrating larger devices becomes feasible. These results open up the inherently well-suited and scalable platform of quantum dots to emulate novel quantum states of matter.