Building topology dot by dot

In the past years, systems of coupled quantum dots with superconducting contacts have appeared as a promising platform for engineering topological superconductivity and Majorana bound states. In particular, these systems offer a way to mitigate the problem of disorder that most likely affected previous nanowire experiments.

In this talk I will explain how the physics of an Andreev bound state allows to implement a tuneable superconducting coupler necessary for driving a chain of quantum dots into the topological regime. I will then review how this effect can be used to implement short Kitaev chains, and how recent experiments compare to our theoretical understanding.

Short Kitaev chains limit the protection of Majorana bound states that can be achieved. This is reflected in the fact that these states in short chains are commonly referred to as “poor man’s Majoranas”. I will discuss strategies to scale these systems up to longer chains exhibiting true topological protection, as well as discuss the prospects of using poor man’s Majoranas to show non-Abelian statistics.