YQuantum, a new start-up in the SNI network, has been based at Park Innovaare in Villigen since January 2025. The four-person team behind this fledgling company produces innovative, miniaturized and scalable hardware for quantum computers and is already in the process of delivering its first products to customers. We spoke to YQuantum’s CEO, Dr. Christian Jünger, to learn more about the company.

The initial idea of establishing YQuantum emerged about a year ago while Dr. Christian Jünger and Dr. Johannes Herrmann were working at QuantrolOx, a company that seeks to advance the automation of quantum computers. Through extensive contact with hardware manufacturers in the quantum computing sector, the two young scientists discovered that there are hardware gaps when it comes to integrating high-frequency components and quantum objects.

“We both have quite extensive and complementary knowledge,” explains Jünger. “Johannes gained considerable experience through his doctoral dissertation and postdoc in the fields of high-frequency technology and quantum engineering at ETH Zurich. Likewise, I worked intensively with superconducting qubits as part of my postdoc at the University of California, Berkeley. With this in mind, we increasingly concluded that we should use our combined knowledge to develop better hardware components, thereby supporting other researchers and companies with the further development of quantum computing.” As their third cofounder, the researchers brought on board the retired Professor Christian Schönenberger, who was director of the SNI for many years and also formerly led the Quantum- and Nanoelectronics group at the Department of Physics at the University of Basel. The team is further enhanced by Dr. Deepankar Sarmah, who also hails from the University of Basel and specializes in nanofabrication and low-
temperature quantum transport measurements.

Great conditions for starting a business
At Park Innovaare in the Canton of Aargau, the young start-up from the University of Basel enjoys ideal conditions for launching a successful business. Proximity to various cooperation partners at the Paul Scherrer Institute and the University of Basel combines with excellently equipped new clean rooms to provide optimum conditions for quickly testing and supplying valuable products. Moreover, a research partnership with the University of California, Berkeley (USA), allows this start-up from the University of Basel to develop prototypes on an international basis by working with leading teams of scientists in the field of quantum computing.

Necessary miniaturization
Specifically, the scientists are working on the miniaturization of various components needed in quantum computers. For example, Jünger and Herrmann have just applied for a patent on an integrated infrared filter. Filters of this kind are necessary because quantum bits (qubits) — the tiny, extremely sensitive units of a quantum computer — must be protected against interference from the environment. The filter developed by YQuantum ensures that interference in the form of electromagnetic noise, thermal effects or individual photons is attenuated and that the qubits retain their quantum states. It is also significantly smaller than existing filters, which will be a key factor when it comes to realizing a greater number of qubits in the future.

“For most concepts of a quantum computer, you need very low temperatures close to absolute zero, which are achieved within a cryostat,” explains Jünger. “For every chip with qubits, you then also need numerous high-frequency components within the cryostats — and all of these components take up space. Building genuinely powerful quantum computers will require far more qubits than in current approaches. This also means that more components such as filters and amplifiers will need to be integrated into the cryostats. That’s where we come in — because we offer smaller, optimized components, all of which are scalable.”

Already available
YQuantum already has two products on the market and is currently supplying them to its first customers. One of the products is a DC block — a small device that provides clean and controlled grounding, thereby eliminating unwanted electrical currents that could distort measurement results or interfere with sensitive qubits. The other product offered by YQuantum is a bias tee, which can, for example, be used to supply a component with electricity while simultaneously controlling it via high-frequency signals without the two signals interfering with one another. “This component ensures that communication between two qubits achieves a higher quality factor,” says Jünger. “It also allows us to improve quantum computing, although we often have to do a bit of educating — because some users aren’t aware of the imperfections of their current solutions.”

Partner in a Nano-Argovia project
Since the start of this year, YQuantum has also been participating as an industrial partner in a Nano-Argovia project. Together with researchers from the University of Basel and the Paul Scherrer Institute, the team is developing an amplifier that converts weak signals from a quantum computer into classical electrical signals without additional noise, paving the way for precise and scalable quantum control.

“We have plenty of other ideas about which components we can optimize and miniaturize in order to make quantum computers faster, more stable, and scalable,” says Jünger. Most of the projects are initially designed for superconducting quantum computers, but they can generally also be used for other concepts, such as the spin-based quantum computer that is the subject of research at the University of Basel. In developing these innovative concepts, the young entrepreneurs apply knowledge they acquired in various world-leading research groups in Switzerland and the USA. Through a combination of quantum physics, nanoscience and engineering, they are ensuring that the whole is greater than the sum of its parts.

Although the company name is pronounced “Why Quantum?”, that is actually no longer the question for this four-person team of scientists. These days, they’re more interested in how quickly powerful quantum computers can be developed and how YQuantum can support its customers with the development process.

Further information:

YQuantum