Quantum Coherence Lab

Zumbühl Group

 
 

Welcome to the web page of the Quantum Coherence Lab

Research focuses on quantum transport experiments investigating quantum coherence, electron spins and nuclear spins and interactions in semiconductor and graphene nanostructures. Ongoing projects include

  • spin qubits in coupled, laterally gated GaAs quantum dots
  • microkelvin temperatures in nanoscale sample
  • novel quantum states of matter, such as electron or nuclear spin helices, topological states and Majorana fermions
  • spin-orbit coupling in GaAs quantum wells
  • experiments investigating mesoscopic electron transport, including graphene nanoribbon research

We are interested in coherent manipulation of individual quantum systems in solid state nanostructures with quantum computation as a long term goal.

Experiments investigate quantum transport through semiconductor nanostructures which are fabricated in house using high mobility 2D electron gas materials obtained from collaborating molecular beam epitaxy labs. Experiments are typically performed in dilution refrigerators at millikelvin temperatures in  magnetic fields. Measurements are done using electronic low-noise techniques and may involve nanosecond-pulsing and microsecond readout schemes.

An ERC Starting Grant from the first ERC call was awarded to our group and boosted our research from 2008-2013 (press release)

Positions are currently available, please see the positions page.

 

Affiliations and Collaborations

 We are affiliated with

Our group enjoys numerous ongoing collaborations, including the following groups (in arbitrary order)

 

Upcoming Events

17 Nov 13:15

1.09

Bilal

21 Nov 14:00

Hörsaal 1

PhD Defense Pirmin

24 Nov

1.09

Dies Academicus

1 Dec 13:15

1.09

Group Meeting

 

News from the lab

Hyperfine-phonon spin relaxation paper appeared on arXiv, reporting spin lifetimes of up to one minute in a GaAs single electron quantum dot

Understanding and control of the spin relaxation time T1 is among the key challenges for spin based qubits. A larger T1 is generally favored, setting the fundamental upper limit to the qubit coherence and spin readout fidelity. We establish the prediction of hyperfine-phonon spin relaxation experimentally, by measuring T1 over an unprecedented range of magnetic fields and report a maximum T1=57±15 s at the lowest fields, setting a new record for the spin lifetime in a nanostructure.

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News from the Physics Department

A nanoscale balance for individual cells

An interdisciplinary team from the University of Basel, ETH Zurich, and University College London have developed a new method that can be used to analyze individual live mammalian cells within a cell assembly. Based on a system of tiny cantilever probes, the technique records the cell mass over several days in millisecond steps and is accurate to within a few picograms. Using the new technique, the scientists have been able to observe for the first time that the cell mass fluctuates within the space of a few seconds. These findings and the new platform provide fundamental insights into the regulation of cell mass and into how this is disrupted in the event of illness. The study was presented today in the journal Nature.

 

 

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