Quantum RF Engineer

Founded in 2020 and based in the heart of Paris, C12’s mission is to be at the center of one of the biggest technological breakthroughs of the century and change the course of history by building a universal quantum computer.

At C12, we believe that achieving a true breakthrough in quantum computing requires rethinking the fundamentals. That’s why our founders—deeply rooted in academic and engineering excellence—have chosen carbon nanotubes as the building blocks of our quantum processors. This ultra-pure material dramatically reduces error rates, boosts performance, and minimizes hardware overhead—key ingredients for scalable, fault‑tolerant quantum computing. By crafting a unique approach that scales, we aim to revolutionize quantum computing just as silicon transformed classical computing.

Since our founding, we’ve raised over €25 million in funding, published 11 scientific papers, and secured 8 patents. Today, our fast‑growing team of 90 people, including over 20 PhDs, has more than 20 nationalities represented. We have our own cutting‑edge lab spaces in Paris’ historic Panthéon district, where scientists, engineers, and innovators work side‑by‑side to tackle some of the most exciting technical challenges of our time.

If you’re passionate about shaping the future of quantum technology and want to make a real impact, C12 offers a unique environment to grow, learn, and innovate.

Your role at C12 Quantum Electronics

As Quantum RF Engineer your main responsibility will be contributing to the design & optimisation of passive and active on‑chip microwave components for qubit control, qubit‑qubit interfacing and qubit readout.

You will be performing EM and circuit simulations for individual components and integrated systems along with contributions to cryogenic measurements for component and system performance verification.

Key responsibilities

• Design and conduct simulations of DC, RF and microwave on‑chip components
• Contribute to cryogenic measurement
• Contribute to the continuous improvement of our Python‑based design repository and integration with simulation workflow
• Be occasionally involved in the design of mechanical parts (Fusion 360, SolidWorks…) and PCBs

About you

• Have at least a Master’s degree in Quantum Physics (preferred), Applied Physics, Electrical Engineering, Nanotechnology or Nanoscience or other related disciplines
• Have some previous experience designing and integrating RF & microwave components and subsystems
• Have previous electromagnetic simulations experience using industry standard tools such as HFSS, SONNET, ADS, Comsol
• Have experience with high‑frequency (RF, microwave or mm‑wave), IC or PCB design
• Have experience with chip design layout tools like Klayout or L‑Edit
• Be capable of designing and developing in Python
• Have great communication skills in English (oral and written)

Really nice to have

• Experience with cryogenic RF and DC measurement
• Knowledge of semiconductor device physics and micro‑fabrication processes
• Knowledge of fabrication principles and the constraints they impose on physical device parameters

What we offer

• 55,000 euros – 62,000 euros yearly base salary
• Stock options for every employee (BSPCE/ESOP)
• Sponsored trip to conferences around the world
• A highly dynamic international team
• Swile meal vouchers
• Mental health support with Moka.care
• Training budget / Annual Learning & Development Allowance
• Sabbatical leave (after 2 years in the company)
• Vibrant office culture (two office spaces in the heart of Paris, team lunches, offsite events, Friday breakfasts)

You should join us if

• You want to have a key role in a growing startup with challenges at the frontier of the technology
• You want to contribute to achieving landmark results in quantum computing, making a difference in the emerging quantum technologies
• You want to work within a 60‑people team with various backgrounds in nanofabrication, quantum electronics, and carbon nanotube science to create a revolutionary quantum computing processor
• You want to thrive in an exceptional scientific environment with several industrial and academic partners
• You share our values (excellence, scientific integrity, diversity, curiosity, and care) and want to help us define our product‑focused culture and ambition to accelerate

We still encourage even if you don’t meet all the requirements. Rest assured, we are committed to finding the right fit for our team and are open to adjusting compensations based on skills and experiences. Applications from women are especially welcomed.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analysing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgement. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.