We demonstrate microwave measurements of the Andreev-bound-state (ABS) spectrum in
planar Josephson junctions (JJs) defined in Ge high-mobility two-dimensional hole gases …

The tunneling of Cooper pairs across a Josephson junction (JJ) allows for the nonlinear
inductance necessary to construct superconducting qubits, amplifiers, and various other …

Gatemon qubits are the electrically tunable cousins of superconducting transmon qubits. In
this work, we demonstrate the full coherent control of a gatemon qubit based on hole carriers …

Quasiparticle (QP) effects play a significant role in the coherence and fidelity of
superconducting quantum circuits. The Andreev bound states of high-transparency …

In the presence of a 4π-periodic contribution to the current phase relation, for example in
topological Josephson junctions, odd Shapiro steps are expected to be missing. While …

This thesis sets out to explain why experiments with the gatemon qubit have yielded lower
than predicted 𝑇1 times. To do this it gives a short introduction to circuit QED and the …