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 over 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.

Role overview :

As Quantum RF Engineer your main responsibility will be contributing to the design & optimization of passive and active on-chip microwave components for qubit control, qubit-qubit interfacing and qubit read

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

Responsibilities:

• Design and simulation of DC, RF and microwave on-chip components
• Contributing to the cryogenic measurement
• Contributing to the continuous improvement of our python based design repository and integration with simulation workflow
• Occasional involvement in design of mechanical parts (Fusion 360, SolidWorks…) and PCBs.

About you:

• At least Master's degree in Quantum Physics (preferred), Applied Physics, Electrical engineering, Nanotechnology or Nanoscience or other related disciplines
• Previous experience designing and integrating RF & microwave components and subsystems:
• Previous electromagnetic simulations using industry standard tools such as HFSS, SONNET, ADS, Comsol
• High-frequency (RF, microwave or mm-wave), IC or PCB design
• Previous experience with chip design layout tools like Klayout, L-Edit
• Design/development in Python
• Great communication in English (verbal and written)

Really nice to have:

• Previous experience with cryogenic RF and DC measurement
• Knowledge of semiconductor device physics and microfabrication processes
• Knowledge of fabrication principles and the constraints they impose on physical device parameters

What we offer:

• Flexible rhythm of remote work
• Stock options for every employee (BSPCE/ESOP)
• Two office spaces in the heart of Paris (both next to the famous Panthéon!)
• Sponsored trip to conferences around the world
• Swile meal vouchers
• Breakfast for all every Friday
• Mental health support with moka.care
• Training budgets/ Annual Learning & Development Allowance
• Sabbatical leave (after 2 years in the company)

You should join us if you...

• 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.

€55,000 - €62, 000 a yearWe still encourage you to apply, 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 compensation based on skills and e xperience.

C12 encourages all who feel qualified to apply, recruitment decisions are based solely on qualifications, skills, knowledge and experience. Applications from women are particularl y welcomed.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.