Dominic Lennon from the group of Dr. Natalia Ares, Oxford University, has started a user access project on the Basel node of the European Microkelvin Platform (EMP). The project is working to implement machine learning to search for Pauli spin blockade in Ge/Si core/shell nanowire quantum dots for spin qubits.
The consortium consisting of Uni Basel, TU Eindhoven, Uni Twente and IST Vienna plus start-ups nano-PHAB and BASPI is setting out to explore Majorana fermions in Ge/Si core/shell nanowires. The hole carriers in this system are subject to very strong confinement, a thin, protective shell facilitating proximitization yet preventing metalization, potentially strong electron-electron interactions, and finally, large and tunable spin-orbit coupling and g-factor.
We study theoretically the Dresselhaus spin-orbit interaction (SOI) in zinc-blende nanowires of various growth directions. While the Dresselhaus SOI is suppressed for select directions and confinements, many configurations allow for a strong Dresselhaus SOI. A similarly strong Rashba term can be gate-induced, providing a means to switch the SOI on and off. Remarkably high Dresselhaus SOI energies ~millielectronvolt are expected for narrow diameter InSb nanowires. Carbadillo, Kloeffel, et al. arXiv:1910.00562.
Machine learning algorithm performing fully automatic measurements on the GaAs quantum dot, guessing most informative measurements using probabilistic deep-generative model, giving a speed-up of about a factor of 4. Collaboration with Natalia Ares' team (Oxford), Edward Laird (Lancaster) and our Basel team... with fully automated measurements, we hope to facilitate scaling to a large number of qubits. npj Quantum Information volume 5, Article number: 79 (2019).
SNI News "Machine Learning at the Quantum Lab"...
Simon Svab successfully completed his MSc thesis "g-factor anisotropy in a lateral GaAs spin qubit" and presented his results to the group today. Congratulations, Simon, on an outstanding thesis, and thanks very much for all the work! After more than 20 years of GaAs quantum dots, the first experiment to demonstrate the ca. 10% anisotropy of the spin splitting!