University of Basel

Department
of Physics

Quantum Coherence Lab - Zumbühl Group

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On arXiv: Ultrafast Hole Spin Qubit with Gate-Tunable Spin-Orbit Switch

We demonstrate an ultrafast qubit with Ge/Si core/shell hole spins, with spin-flipping times as short as ~1 ns - a new record for a single-spin qubit. Next, we show a large degree of electrical control over the Rabi frequency, Zeeman…
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Review on Cooling Nanoelectronic Devices Published!

Review "Progress in Cooling Nanoelectronic Devices to Ultra‑Low Temperatures" from Lancaster and our group published in Journal of Low Temperature Physics! doi.org/10.1007/s10909-020-02472-9
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Rafael Eggli has joined the group to work on project thesis

Rafael Eggli (Nanoscience BSc, Basel) joined the group this week to work on his project thesis. He is working on FinFET Quantum dot devices in collaboration with Andreas Kuhlmann. Welcome to the Group, and looking forward to work with you!
MeinArbeitsplatz

Our Lab has been featured in UniNova

The article revolves around a typical work flow in our Cryolab including the transfer of Helium and the control of the measurement.
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Published in Nano Letters: Remote Doping of Scalable Nanowire Branches

Selective-area epitaxy provides a path toward high crystal quality, scalable and complex nanowire networks. Here, we demonstrate remote-doping in InGaAs nanowire networks and find weak anti-localization—a signature of strong spin–orbit…
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On arXiv: Out-of-plane corrugations in graphene based van der Waals heterostructures

2D materials are often envisioned as flat monoatomic truly 2D layers. However, out-of-plane corrugations are inevitably present. In an in-plane magnetic field, the ripples lead to random, inhomogeneous perpendicular fields, causing…
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Luca Forrer defends MSc thesis

Luca Forrer successfully completed his MSc thesis "Quantum Transport in Templated Indium Arsenide Nanowires" and defended his results in the group (on zoom). In this collaboration with Prof. Anna Fontcuberta i Morral’s group, the InAs wires…
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On arXiv: Edge State Wave Functions from Tunneling Spectroscopy

We use the lowest five modes of a quantum wire to probe adjacent quantum Hall edge state in tunneling spectroscopy. We self-consistently solve the Poisson-Schrödinger equations to simulate the spectroscopy, reproducing the experiment in…
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TOPSQUAD kick-off meeting in Twente!

Kick-off meeting TOPSQUAD FET open TOpologically Protected & Scalable QUAntum bits, at the University of Twente from where it is coordinated, with partners Uni Basel, TU Eindhoven and IST Austria, plus spin-offs https://baspi.ch and…
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Simon Svab joins groups as PhD student!!

With a MSc from our group and a BSc in Nanosciences from the University of Basel, Simon Svab is starting his PhD thesis on the TOPSQUAD FET project on topological states in Ge/Si nanowires. Welcome back to the group, and looking forward to…
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Big week for spin-off Basel Precision Instruments GmbH: shipping out 40 preamps!

After Davide, Sascha and Michael completed, tested and characterized a set of preamps, packing and shipping 40 units to customers around the world is taking place this week! Exciting to ship these instruments on time, for customers to do…
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Prof. Attila Geresdi, Chalmers University, starts EMP access on on-chip Indium demagnetization cooling

Prof. Attila Geresdi, Chalmers University, Sweden, is starting a user access project on the Basel node of the European Microkelvin Platform (EMP). The project is to push the frontier of on-and-off-chip cooling Coulomb blockade thermometers…
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On arXiv: Progress in cooling nanoelectronic devices to ultra-low temperatures

A number of groups worldwide are working to produce sub-millikelvin on-chip electron temperatures, motivated by the possibility to observe new physics and improving quantum device performance. In this review, we focus on on-chip…
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On arXiv: Quantum device fine-tuning using unsupervised embedding learning

We experimentally demonstrate an algorithm capable of fi ne-tuning several device parameters at once. The algorithm acquires a measurement, scores it using a variational auto-encoder, and optimizes gate voltage via the score in real-time in…
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Published in PRB: Symmetry breaking of the persistent spin helix in quantum transport

We introduce a new spin quantization axis via the persistent spin helix, revealing a full decoupling of the Cooperon triplet scattering modes as well as decoupled Landau levels. This makes it possible to derive a closed-form expression for…
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