The Quantum Computing Group at WMI presented a coherent control method for superconducting fluxonium qubits, employing a Purcell‑protected flux line featuring a low‑pass filter. This approach closes the control  hannel at the qubit transition frequency, reducing qubit decay while enabling fast, high‑fidelity control via parametric subharmonic driving at integer fractions of the transition frequency. The scheme supports coherent  control using up to 11‑photon subharmonic drives, with observed Rabi frequencies and induced frequency shifts aligning closely with theoretical models. A three‑photon subharmonic drive is functionally equivalent to on‑resonance driving, achieving single‑qubit gate fidelities exceeding 99.94%. This demonstration establishes a scalable and wiring‑efficient control architecture for fluxonium‑based quantum processors.

Quantum computers are not yet powerful enough to outperform classical computers on complex problems beyond simple demonstrations. To tackle computational challenges of high interest, quantum computers must grow from a few qubits to thousands. Scaling up current quantum processors, such as those based on superconducting qubits, introduces new challenges, such as limited physical space and a growing number of control lines. Our work presents a superconducting qubit architecture designed to address these challenges using frequency-modulated coupling elements. The elements connect multiple qubits and readout components, reducing the number of required control lines without sacrificing controllability. Using a single coupling element, we successfully demonstrate two-qubit interactions, unconditional qubit reset to the ground state, leakage elimination to higher-energy states, and qubit readout. These operations are crucial for building scalable quantum computers and are selectively controlled via the drive frequency of the coupler. This work advances the scaling of quantum computers based on superconducting qubits beyond small-scale applications.

The European consortium OpenSuperQPlus (OSQ+) is making significant strides toward building Europe’s first 100-qubit quantum computer by 2026 — with impressive progress in both qubit number and quality thanks to all its partners. TU Delft has released two scalable prototypes to the cloud, with test benching performed by OrangeQS. Simultaneously, Finnish and German partners, including VTT, IQM Quantum Computers, and Fraunhofer EMFT, are progressing with scaling and chip manufacturing. We are happy that we at the WMI continue to push larger qubit numbers with a 17-transmon QPU.

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🎯 Want to learn more? Join us at the SQA 2025 Conference in Delft, 25–28 August. We’ll discuss benchmarking, calibration, and the path to 100 qubits—with an impressive line-up of international experts, including contributions from WMI.

Superradiance—where groups of excited atoms emit light in a dazzling collective flash—has been widely thought to hinge on complex correlations. Using quantum trajectory unraveling, this work tracks how entanglement builds up in individual decay processes and reveals a surprising result: though the atoms are indeed strongly correlated, you don’t need entangled descriptions to predict superradiant bursts—even in engineered quantum light environments. This surprising result reveals that the global quantum complexity underlying superradiance does not preclude simple, scalable predictions of its local dynamics, opening new paths for controlling collective light emission in quantum technologies and deepening our understanding of light–matter interactions.

The European Union has approved SUPREME, a major new pilot line to industrialise superconducting quantum chip fabrication, involving 23 partners across 8 EU member states, one of the three central fabrication sites will be hosted in Germany and anchored by

· Walther-Meissner-Institute (WMI)
· Technische Universität München
· Peak Quantum
· Max Planck Halbleiterlabor - HLL
· Infineon Technologies AG
· Fraunhofer-Gesellschaft (EMFT, IZM, IPMS, IAF)
· Leibniz Institute of Photonic Technology (Leibniz IPHT)

This collaboration is empowered by the Munich Quantum Valley ecosystem, enabling close coordination between academic research, applied technology development, and industrial-scale fabrication. 

SUPREME will develop and validate high-yield processes for superconducting quantum chips, focusing on technologies such as angle-evaporated and etched Josephson junctions, 3D integration, and hybrid quantum processes. These fabrication techniques are critical for the scaling of quantum processors, sensors, and communication components beyond laboratory prototypes.

Quantum computers are inherently unstable and difficult to control. To enable scalable calibration and stabilization, the new BMFTR Quantum Futur Junior Research Group—led by Benjamin Lienhard at the Technical University of Munich and the Walther-Meissner-Institute—will develop efficient, robust calibration protocols. Drawing inspiration from modern aircraft, whose stable flight paths depend on thousands of sensors, the team will integrate sensing capabilities into quantum processors to enhance their stability. These efforts build on and complement ongoing research at the Walther-Meissner-Institute. The targeted advancements will be instrumental in realizing practical, efficient quantum computers capable of solving complex problems beyond the reach of classical computing. The project, EQuIPS, is funded by the Federal Ministry for Research, Technology and Space (BMFTR).