Swiss quantum-enabling startup Rhonexum has raised $1 million in pre-seed funding, led by QDNL Participations. The round also saw participation from Venture Kick, alongside additional grant funding and non-dilutive support from Swiss innovation programmes, including EPFL Startup Launchpad, Fondation pour l’Innovation Technologique (FIT), and the Swiss National Science Foundation (SNSF). This combination of equity and grant support provides both financial stability and validation of its technology.
The fresh capital will be used to accelerate product development, expand the company’s design team, and bring its first industrial-grade cryogenic electronics product to an initial group of customers later this year.
Tackling quantum computing’s scaling challenge
Quantum computing has long promised transformative breakthroughs, but scaling these systems remains one of the field’s toughest challenges. A major bottleneck lies in the electronics required to control qubits, the fundamental building blocks of quantum machines.
Rhonexum is addressing this limitation by designing electronics that operate directly at cryogenic temperatures, close to absolute zero. These extreme conditions are essential for maintaining qubit stability, yet conventional electronics struggle to function reliably in such environments.
By placing control electronics closer to the qubits, Rhonexum reduces system complexity and improves performance. This approach has the potential to unlock more scalable quantum architectures, a key step toward practical and commercially viable quantum computers.
What was the origin of this idea?
Regarding the motivation behind this idea, Rhonexum said, “The company was founded at the intersection of a clear market need and a strong personal motivation for innovation. From a market perspective, cryogenic electronics is widely recognised as a major bottleneck in scaling quantum computers, particularly due to the lack of reliable cryogenic device models and design tools. From a personal perspective, the founders were motivated by the challenge of building a technology from the ground up and translating advanced academic research into an industrial and commercial context.”
Built from deep-tech expertise
Rhonexum was founded in November 2025 in Lausanne, Switzerland, as a spin-out from the AQUA Lab at EPFL. The company brings together deep scientific expertise and practical engineering experience.
In response to TFN, Rhonexum said, “Hung‑Chi Han is a co-founder and CTO of Rhonexum. He completed his PhD at EPFL, focusing on cryogenic device modelling and characterisation of advanced silicon technologies for quantum computing. He has participated in several European research projects and gained industry experience at TSMC, where he worked on advanced semiconductor nodes at cryogenic temperatures. His background spans electronic device physics, solid‑state physics, and elements of quantum physics.”
“Vicente Carbon is a co-founder of Rhonexum. He was born in Spain and followed a French education before joining EPFL in 2019, where he studied microengineering and later completed a master’s degree in robotics. During his studies, he worked closely on challenges related to cryogenic electronics and data acquisition. He also completed an internship at LEM Surgical AG, where he gained exposure to startup execution beyond pure engineering, including the transition from technical concepts to market‑ready solutions,” they replied.
With its first product set to reach early customers soon, Rhonexum is positioning itself at the forefront of quantum hardware innovation. By solving one of the field’s most persistent engineering challenges, the startup could play a pivotal role in shaping the next generation of scalable quantum systems.
What about diversity?
Regarding diversity statistics, the company told TFN, “Hung-Chi Han is from Taiwan, and Vicente Carbon has French and Spanish origins and has a Portuguese background. Rhonexum brings together contributors from six other countries, reflecting the international and cosmopolitan nature of Switzerland’s deep‑tech ecosystem. This diversity of backgrounds supports a wide range of perspectives in engineering, research, and product development, aligned with the company’s international outlook.”
Engineering electronics for extreme environments
At the heart of Rhonexum’s innovation is its ability to develop semiconductor devices that perform under cryogenic conditions. Using proprietary models and software tools, the company designs electronics compatible with standard semiconductor manufacturing processes.
This is a crucial advantage. Rather than requiring entirely new fabrication methods, Rhonexum’s solutions can integrate with existing chip production infrastructure, making them more accessible for industry adoption.
The company’s technology allows electronics to function directly within cryogenic systems, eliminating the need for complex external connections between room-temperature and ultra-cold environments. This not only enhances efficiency but also simplifies the overall system design.
How is Rhonexum different from others?
Rhonexum distinguishes itself in the quantum computing ecosystem through a dual strategy integrating advanced cryogenic electronics and a groundbreaking simulation platform. The company’s technological foundation centres on standard CMOS semiconductor technology, precisely adapted to function at temperatures near absolute zero.
This methodology is recognised across the industry, with various startups and quantum organisations considering cryogenic CMOS electronics a pivotal enabler for miniaturisation, enhanced scalability, and smooth adoption of established semiconductor supply chains.
It should be noted, however, that while this approach is innovative, Rhonexum is not the only entity pursuing it. Other startups are adopting similar strategies, inspired by the evolution of classical computing: whereas early computers filled entire rooms and processed only bytes of information, today’s devices fit in the palm of a hand and store terabytes of data. The quest for miniaturisation and optimisation in quantum computing mirrors this ongoing trend and poses a challenge for many in the sector.
What truly sets Rhonexum apart is its proprietary simulation tool, designed to revolutionise the product development process. This sophisticated platform allows engineers to simulate and validate circuit performance at cryogenic temperatures before fabrication. By virtually prototyping circuits, Rhonexum substantially reduces the number of design iterations necessary, avoids unnecessary manufacturing cycles, and lowers overall development costs. This not only accelerates the company’s time-to-market but also permits a rapid response to shifting customer needs and technological advancements. The simulation tool’s flexibility enables Rhonexum to remain agnostic regarding transistor types, affording clients greater customisation and adaptability in circuit designs.
In summary, Rhonexum’s competitive edge stems from two principal areas: first, its innovative cryogenic CMOS product portfolio, which stands at the forefront of quantum hardware development but is also pursued by peers; second, its unique simulation platform, which confers a decisive advantage in speed, adaptability, and cost-effectiveness. Together, these strengths allow Rhonexum to deliver sophisticated, scalable, and tailored solutions for the quantum computing industry, solutions capable of meeting both current market demands and future technological breakthroughs.
Looking ahead
Over the next three to five years, Rhonexum aims to build a comprehensive catalogue of cryogenic integrated circuit building blocks. Cryogenic electronics currently lack the standardised functional blocks available at room temperature, requiring most circuits to be redesigned from scratch.
The company’s objective is to progressively develop these essential building blocks, enabling customers to integrate them into larger systems and, eventually, to support customised cryogenic circuits tailored to specific applications.
Vicente Carbon, co-founder of Rhonexum, said. “We founded Rhonexum to become the key provider of cryogenic electronics for scalable quantum computers. Our goals are to enable the transition from lab-sized systems to practical, large-scale machines, optimise thermal-load losses and reduce cabling complexity. Our technology also has future strategic applications beyond quantum, such as in space and advanced sensing.”
Kris Kaczmarek, QDNL Participations investment director, said: “Cryogenic CMOS is an important emerging technology space. Rhonexum stands out with an internal software-driven modelling methodology that enables accurate cryogenic simulation before fabrication, allowing for faster and more cost-effective hardware development. We see real potential here, so we’re proud to support Vicente and Hung-Chi as they work to bring their first product to market.”
