Characterizing the effective g-tensor of hole qubits in planar germanium quantum wells

Electron holes in germanium quantum wells show a promising alternative to producing spin qubits due to their potential for fast all-electrical control mediated by the presence of a strong and tunable spin-orbit interaction. However, the same mechanism leads to a potential drawback as it also increases the qubit's sensitivity to nearby charge fluctuations. In this work, we use a nonsymmetrized multiband k·p theory to investigate the dependence of the qubit's effective g-tensor to experimentally relevant parameters such as strain and electric and magnetic field strength and orientation. We use this information to identify potential operational sweetspots where the effect of charge noise is optimized.