University of Basel

Department
of Physics

Quantum Coherence Lab - Zumbühl Group

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GeSi Holes g-factor renormalization

Strong spin-orbit interaction and g-factor renormalization published in Phys. Rev. Res.

Enhancement of g-factors in a B-field due to strong spin-orbit coupling in Ge/Si core/shell nanowire hole spins! Collaboration with TU Eindhoven, University of Twente and Basel Theory as well as Experiment. Froning, Rancic et al., Phys.…
HeHPurge

Published in Cryogenics: Reducing the hydrogen content in liquid helium

Contamination of liquid helium with hydrogen, even at the low levels of 10s of ppm, can lead to blockage of helium intake capillaries needed to operate 1K pots for experiments below 4K, e.g. 3He and dilution refrigerators, thus bringing…
Qubit Device

/ Research

New Type of Qubit with Tunable Speed and Frequency

Physicists from the University of Basel and the TU Eindhoven have demonstrated a new type of qubit – the basic building block of a quantum computer – where the speed and frequency of operation can be widely tuned with a gate voltage. They…
Mathieu

Mathieu de Kruijf defended his MSc Thesis today

Today, Mathieu de Kruijf (TuE) defended his MSc thesis "Fast cryogenic probing of silicon FinFET devices for quantum computing" online with his TuE committee. Mathieu first studied the spin-orbit interaction of holes confined in silicon…
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PhD position in Spin Qubits in Ge quantum well nanostructures

We are looking for a highly motivated, talented and technology-savvy physics or nanoscience student to join our spin qubit team and work on gate defined spin qubits in Ge quantum wells, starting in Q2 or Q3 of 2021. MSc theses on this are…
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Call for Georg H. Endress Postdoc Fellows

We are looking for outstanding and highly motivated scientists who recently finished a PhD in quantum science and quantum computing. Fellows will be appointed for up to three years, and will be selected on the basis of scientific excellence…
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SNF Early Postdoc.Mobility Fellowship for Leon Camenzind

Leon Camenzind was awarded an SNSF Early Postdoc.Mobility fellowship to join the group of Prof. Seigo Tarucha at the Quantum Functional System Research Group, RIKEN Center for Emergent Matter Science, Tokyo, Japan, as a postdoctoral…
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Interview "Revolution in Quantum Physics" in Fon-Times

Fon-Times Interview mit Dominik Zumbühl. Seit rund zwanzig Jahren läuft die zweite Revolution der Quantenphysik. Neue Experimente führen vor Augen, dass sie die verrückte Welt der Quantenphysik genutzt werden kann, um nützliche Dinge…
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Published in PRB (Editor's Suggestion): Out-of-plane corrugations in graphene heterostructures

Even when sandwiched between atomically flat hBN crystals, surprisingly, graphene still exhibits ripples, even in absence of bubbles. These out-of-plane corrugations reduce mobility and suppress weak localization in an in-plane magnetic…
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On arXiv: Reducing the hydrogen content in liquid helium

Molecular hydrogen can block liquid He (LHe) intake capillaries typically used on 1K pots of many cryostats, causing severe disruption to the experiments. Here, we measure molecular hydrogen content in the liquifier helium gas supply and…
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On arXiv: Isotropic and Anisotropic g-factor Corrections in GaAs Quantum Dots

The spin splitting defines the qubit energy and is one of the fundamental properties of a semiconductor electron in a magnetic field. Here, we measure and separate the isotropic and anisotropic corrections to the bulk g-factor in two GaAs…
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On arXiv: Quantum measurement induced a many-body transition

The act of measurement in quantum mechanics is still mysterious and not microscopically understood. In our work, we show that even a weak (non-projective) measurement of a quantum dot system with an adjacent detector can result in a…
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On arXiv: Deep Reinforcement Learning for Efficient Measurement of Quantum Devices

Deep reinforcement learning is an emerging machine learning approach which can teach a computer to learn from actions and rewards similar to the way humans learn from experience. Here, we use this approach for fully automatic identification…
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Published in New Journal of Physics: Fine-tuning with unsuperv. embedding learning

We 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 an…
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Group Hike to Wissigstock 2'887m

Shot of the brave thirteen who took it upon themselves to hike all the way to the top of Wissigstock at 2'887 meters altitude... refreshed and slightly proud... enjoying the breathtaking view from up there!
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