WMI-Seminar Talk by Matthias Mergenthaler (IBM Research - Zurich) - 10:15am

Title: Effects of surface treatments and UHV packaging on flux tunable transmon qubits

Congratulations to Philipp Krüger

Philipp Krüger of WMI has been awarded a Best Poster Prize for his excellent poster contribution on "Microwave Quantum Key Distribution in a Noisy Environment" presented at the International Conference on Quantum Science & Technology organized by the Excellence Cluster MCQST.

The Best Poster Award has been handed over within the Award Ceremony Session on 23 July 2021 together with a prize money donated by Menlo Systems GmbH.

Obituary for Johneph Sukham †

On July 3, Johneph Sukham died in a tragic accident. We feel great sadness and will miss Johneph as an inspiring colleague and friend. RIP.

Welt der Quanten

There is a tremendous progress in quantum research and the development of quantum technologies, and their application potential is huge. In a focus issue of the journal "Akademie Aktuell" scientists of the Walther-Meißner-Institute explain the present research directions in quantum science and technology. They also discuss the future impact of quantum technology for all of us.

Munich is on of the internationally leading centers for quantum science and technology. This leading position has been further strengthened  by the start of the excellence cluster  Munich Center for Quantum Science and Technology (MCQST) in 2019 and the foundation of the Munich Quantum Valley (MQV) in 2021. The latter will be supported by the Bavarian state government by 300 Mio. Euro. The Walther-Meißner-Institute is one of the key players pushing the dynamic development since almost two decades.


Federico Roy, Nicolas Wittler and Max Werninghaus in a collaboration between Saarland University, IBM Research, Forschungszentrum Jülich and WMI describe how optimal control methods can be used in system characterization to achieve a "Good Model". They outline a new method for Control, Calibration and Characterization (C3) of quantum devices based on the complete understanding of the system and using optimal control. C3 provides us with the tools to achieve this goal and push us further in the quest for high-fidelity quantum devices.

Integrated Tool Set for Control, Calibration, and Characterization of Quantum Devices Applied to Superconducting Qubits
Nicolas Wittler et al., Phys. Rev. Applied 15, 034080 (2021).

Contactless high performance power transmission

A team led by physicists Christoph Utschick and Prof. Rudolf Gross has succeeded in making a coil with superconducting wires capable of transmitting power in the range of more than five kilowatts contactless and with only small losses. The wide field of conceivable applications include autonomous industrial robots, medical equipment, vehicles and even aircraft.

Superconducting Wireless Power Transfer Beyond 5 kW at High Power Density for Industrial Applications and Fast Battery Charging
Christoph Utschick et al., IEEE Trans. Appl. Supercond. 31, 5500110 (2021)

Munich Quantum Valley Kick-Off

To build a quantum computers that can solve complex scientific and economic problems faster than any supercomputer; to create infrastructures that facilitate technology transfer and the exchange of ideas in the field of quantum sciences; to offer excellent education and training opportunities for the specialists of tomorrow.

Learn more about the Munich Quantum Valley Initiative, about the status quo of quantum technologies in Bavaria and about the future opportunities that will arise for Bavaria through the development of these disruptive technologies: Thursday, 04 March 2021 from 10 am - 12 pm (CET) via livestream on Youtube.

Spin Transport and Current-Induced Torques in Superconductor-Ferromagnet Heterostructures

Researchers of WMI in a collaboration with the Norwegian University of Science and Technology at Trondheim and the University of Konstanz  successfully realized the injection of quasiparticle spin currents into a superconductor (NbN) via spin pumping from an adjacent ferromagnetic metal (Py). Using a phase sensitive detection method they can quantitatively extract the spin current-induced torques. Below Tc, they observe a suppression of the damping-like torque and a large field-like current-induced torque.

Temperature-Dependent Spin Transport and Current-Induced Torques in Superconductor-Ferromagnet Heterostructures
Manuel Müller et al., Phys. Rev. Lett. 126, 087201 (2021).

Zeeman Spin-Orbit Coupling and Magnetic Quantum Oscillations in Antiferromagnetic Conductors

Solid-state spin physics arising from spin-orbit coupling is linked to symmetry-protected degeneracies. In an international collaboration researchers of WMI proove that this is also true for Zeeman spin-orbit coupling in antiferromagnetic conductors. They show that the Néel state of the organic conductor κ-(BETS)2FeBr4 shows no spin modulation of the Shubnikov-de Haas oscillations, contrary to its paramagnetic state. A comparative study of the electron-doped high Tc superconductor Nd1.85Ce0.15CuO4  provides clear evidence for the presence of Néel order even at optimal doping.

Zeeman Spin-Orbit Coupling and Magnetic Quantum Oscillations in Antiferromagnetic Conductors
R. Ramazashvili et al., npj Quantum Mater. 6, 11 (2021).

Speeding up quantum gates

Max Werninghaus and Federico Roy at IBM Research in collaboration with Forschungszentrum Jülich and Walther-Meissner-Institute (WMI) experimentally applied optimal control methods to superconducting qubit pulses and achieve a 7-fold reduction of state leakage and a 3-fold reduction of standard errors for fast control pulses.

Leakage reduction in fast superconducting qubit gates via optimal control
Max Werninghaus et al., npj Quantum Inf. 7, 14 (2021)

Quantum Computing in Germany

Building a quantum processor with novel properties based on superconducting qubits - this is the aim of the four year project GeQCoS ('German Quantum Computer based on Superconducting Qubits') funded by the BMBF that we aim to realize at the WMI (Bavarian Academy of Sciences) in collaboration with Infineon Technologies, University of Erlangen-Nuremberg, University of Karlsruhe and Fraunhofer-Gesellschaft.

Munich Quantum Valley

The Bavarian Academy of Science and Humanities, the Fraunhofer Society, the Max Planck Society for the Advancement of Science and both Munich Universities LMU and TU Munich join forces to estalish the Munich Quantum Valley to push forward research and innovation in quantum technologies and quantum computing. 

Pseudospin in antiferromagnets

A team of researchers from the Technical University of Munich (TUM), the Bavarian Academy of Sciences and Humanities (BAdW) and the Norwegian University of Science and Technology (NTNU) in Trondheim has discovered an exciting method for controlling spin carried by quantized spin wave excitations in antiferromagnetic insulators.

Observation of Antiferromagnetic Magnon Pseudospin Dynamics and the Hanle Effect
Tobias Wimmer et al.,  Phys. Rev. Lett. 125, 247204 (2020).

The Return of the Spin Echo

A team of researchers from the Technical University of Munich (TUM), TU Wien (Vienna University of Technology) and the Bavarian Academy of Sciences and Humanities have discovered a remarkable spin echo effect – this effect presents exciting, new opportunities for working with quantum information.

Echo Trains in Pulsed Electron Spin Resonance of a Strongly Coupled Spin Ensemble
S. Weichselbaumer et al., Physical Review Letters 125, 137701 (2020)