Quantum Coherence Lab

Zumbühl Group


News from our Group

FET project TOPSQUAD launched: TOpologically Protected and Scalable QUAntum Bits

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.


New on the arXiv: Low-symmetry nanowires for enhanced Dresselhaus spin-orbit interaction

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.


Published in npj Quantum Information: Efficiently measuring a quantum device using machine learning

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 presents his MSc thesis research

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! 


Luca Forrer and Pascal Würsch have joined the group to work on MSc theses

Luca Forrer (Nanoscience BSc, Basel) and Pascal Würsch (Physics BSc, ETHZ) joined the group this week to work on their MSc theses. Luca is working on quantum transport in templated III-V nanowires. Pascal is working on sub-mK quantum dot thermometery on the microkelvin project. Welcome to the group, and looking forward to work with you!