Quantum Error Correction Intern

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 close to €40 million in funding, published 11 scientific papers, and secured 8 patents. Today, our fast-growing team of 60, including 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.

Goal of the Internship :
As part of the Theory team, you will implement numerical simulations for selected directional codes and benchmark several decoders on these codes under a relevant noise model. The internship will provide a comparative study: logical error rates vs. physical error rates (and runtime) and allow for the investigation of the possibility of increasing the encoding rates with increased connectivity.

Specific tasks::
• Understand the basics concepts of Quantum Error Correction (QEC), e.g. data qubits, measure qubits, parity checks, logical qubits, circuit level noise, decoding algorithms
• Understand the construction of directional codes
• Select a few candidates for benchmarking, with around 60 data qubits
• Implement their parity check matrices in Python, generate their syndrome extraction circuit using Stim and insert errors to the circuit (using Callisto-inspired noise model)
• Compare their logical error rates via Monte Carlo simulations, using a few decoders (eg.BP+OSD,Tesseract,Relay-BP)
• Explore machine learning based code discovery to extend the construction of these codes

About You::
• You speak English fluently
• You have strong background in quantum physics and linear algebra
• You have completed courses in quantum information or quantum computing
• You have Python programming skills
• You are curious to learn more about quantum error correction, and work in a start-up environment

You should join us if...

You like hands-on work and 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.

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