Senior Quantum Error Correction Scientist

ParisFull - time

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 75, including 20 PhDs, has over 25 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 a Senior Quantum Error Correction (QEC) Scientist , you will play a central role in shaping C12's fault-tolerant quantum computing strategy.

You will design, analyze, and optimize fault-tolerant architectures tailored to our carbon nanotube-based spin qubit platform, working at the intersection of theory, simulation, and hardware constraints.

You will contribute directly to the development of scalable, fault-tolerant quantum processors by practical implementation of abstract QEC protocols. This includes defining building blocks of the fault-tolerant architecture, evaluating thresholds, connectivity requirements and guiding experimental implementations in close collaboration with hardware and control teams.

Your work will be crutial in determining the path toward achieving logical qubit performance exceeding that of physical qubits, a key milestone for practical quantum advantage.

Key Responsibilities: Design and develop QEC codes and fault-tolerant architectures adapted to C12's qubit technology or adapt existing solutions

Analyze noise models and error channels specific to carbon nanotube spin qubits and translate them into QEC performance metrics

Collaborate closely with experimental teams to align QEC protocols with hardware constraints and roadmap

Contribute to the design of decoding algorithms and error mitigation strategies compatible with QEC schemes

Stay at the forefront of advances in QEC theory and integration relevant innovations into C12's architecture

Mentor junior researchers and contributes to building C12's QEC expertise

About you: You are fluent in English

You hold a PhD in Physics, Applied Mathematics, Computer Science or a closely related field

You have at least 2-5 years of experience in quantum computing research (academic or industrial)

You have strong expertise in quantum error correction, fault-tolerant quantum computing or quantum information theory

You have experience with numerical simulations and relevant tools (e.g. Python, Qiskit, Stim)

You understand realistic noise processes and their impact on quantum circuits

What we offer: Stock options for every employee (BSPCE/ESOP)

Two office spaces in the heart of Paris (both next to the Panthéon)

Sponsored trip to conferences around the world

Swile meal vouchers

Vibrant office culture (team lunches, offsite events, Friday breakfasts..)

Mental health support with moka.care

Training budget/ Annual Learning & Development Allowance

Sabbatical leave (after 2 years in the company)

You are fluent in English